feat(losses): списание со склада с указанием причины (P1-2)

Domain Loss+LossLine + enum LossReason (Defect/Expired/Damage/Shortage/Other).
EF, миграция Phase6b_Losses. Контроллер api/inventory/losses: CRUD +
Post/Unpost. Post создаёт StockMovement тип WriteOff с -Quantity; защита
от ухода в минус (409 со списком конфликтов). Unpost возвращает товар.
Web: /inventory/losses (list+edit) с фильтром по причине и колонкой
текущего остатка в строке. Сайдбар: «Списания» (Admin/Storekeeper).

Тесты: 3 интеграционных (post→stock падает, unpost восстанавливает;
списание сверх остатка → 409; tenant-изоляция).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/food-market.api/Controllers/Inventory/LossesController.cs

@@ -0,0 +1,393 @@
+using System.ComponentModel.DataAnnotations;
+using foodmarket.Application.Common;
+using foodmarket.Application.Inventory;
+using foodmarket.Domain.Inventory;
+using foodmarket.Infrastructure.Persistence;
+using foodmarket.Api.Infrastructure.Authorization;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+
+namespace foodmarket.Api.Controllers.Inventory;
+
+/// <summary>Списание (Loss): уменьшение склада с указанием причины
+/// (брак/просрочка/повреждение/недостача/прочее). При проведении создаёт
+/// <see cref="StockMovement"/> тип <see cref="MovementType.WriteOff"/> с
+/// отрицательным Quantity. Unpost блокируется проверкой не нужно (мы
+/// добавляем обратно — остаток всегда увеличится).</summary>
+[ApiController]
+[Authorize]
+[Route("api/inventory/losses")]
+public class LossesController : ControllerBase
+{
+    private readonly AppDbContext _db;
+    private readonly IStockService _stock;
+
+    public LossesController(AppDbContext db, IStockService stock)
+    {
+        _db = db;
+        _stock = stock;
+    }
+
+    public record LossListRow(
+        Guid Id, string Number, DateTime Date, LossStatus Status, LossReason Reason,
+        Guid StoreId, string StoreName,
+        Guid CurrencyId, string CurrencyCode,
+        decimal Total, int LineCount,
+        DateTime? PostedAt);
+
+    public record LossLineDto(
+        Guid? Id, Guid ProductId, string? ProductName, string? ProductArticle,
+        string? UnitSymbol,
+        decimal Quantity, decimal UnitCost, decimal LineTotal, int SortOrder,
+        decimal? StockAtStore);
+
+    public record LossDto(
+        Guid Id, string Number, DateTime Date, LossStatus Status, LossReason Reason,
+        Guid StoreId, string StoreName,
+        Guid CurrencyId, string CurrencyCode,
+        string? Notes,
+        decimal Total, DateTime? PostedAt,
+        IReadOnlyList<LossLineDto> Lines);
+
+    public record LossLineInput(
+        Guid ProductId,
+        [Range(0, 1e10)] decimal Quantity,
+        [Range(0, 1e10)] decimal UnitCost);
+
+    public record LossInput(
+        DateTime Date, Guid StoreId, Guid CurrencyId, LossReason Reason,
+        string? Notes,
+        IReadOnlyList<LossLineInput> Lines);
+
+    [HttpGet]
+    public async Task<ActionResult<PagedResult<LossListRow>>> List(
+        [FromQuery] PagedRequest req,
+        [FromQuery] LossStatus? status,
+        [FromQuery] LossReason? reason,
+        [FromQuery] Guid? storeId,
+        CancellationToken ct)
+    {
+        var q = from l in _db.Losses.AsNoTracking()
+                join st in _db.Stores on l.StoreId equals st.Id
+                join cu in _db.Currencies on l.CurrencyId equals cu.Id
+                select new { l, st, cu };
+
+        if (status is not null) q = q.Where(x => x.l.Status == status);
+        if (reason is not null) q = q.Where(x => x.l.Reason == reason);
+        if (storeId is not null) q = q.Where(x => x.l.StoreId == storeId);
+        if (!string.IsNullOrWhiteSpace(req.Search))
+        {
+            var s = req.Search.Trim().ToLower();
+            q = q.Where(x => x.l.Number.ToLower().Contains(s));
+        }
+
+        var total = await q.CountAsync(ct);
+        q = (req.Sort, req.Desc) switch
+        {
+            ("number", false) => q.OrderBy(x => x.l.Number),
+            ("number", true) => q.OrderByDescending(x => x.l.Number),
+            ("store", false) => q.OrderBy(x => x.st.Name).ThenByDescending(x => x.l.Date),
+            ("store", true) => q.OrderByDescending(x => x.st.Name).ThenByDescending(x => x.l.Date),
+            ("status", false) => q.OrderBy(x => x.l.Status).ThenByDescending(x => x.l.Date),
+            ("status", true) => q.OrderByDescending(x => x.l.Status).ThenByDescending(x => x.l.Date),
+            ("reason", false) => q.OrderBy(x => x.l.Reason).ThenByDescending(x => x.l.Date),
+            ("reason", true) => q.OrderByDescending(x => x.l.Reason).ThenByDescending(x => x.l.Date),
+            ("total", false) => q.OrderBy(x => x.l.Total).ThenByDescending(x => x.l.Date),
+            ("total", true) => q.OrderByDescending(x => x.l.Total).ThenByDescending(x => x.l.Date),
+            ("date", false) => q.OrderBy(x => x.l.Date).ThenBy(x => x.l.Number),
+            _ => q.OrderByDescending(x => x.l.Date).ThenByDescending(x => x.l.Number),
+        };
+        var items = await q
+            .Skip(req.Skip).Take(req.Take)
+            .Select(x => new LossListRow(
+                x.l.Id, x.l.Number, x.l.Date, x.l.Status, x.l.Reason,
+                x.st.Id, x.st.Name,
+                x.cu.Id, x.cu.Code,
+                x.l.Total,
+                x.l.Lines.Count,
+                x.l.PostedAt))
+            .ToListAsync(ct);
+
+        return new PagedResult<LossListRow> { Items = items, Total = total, Page = req.Page, PageSize = req.Take };
+    }
+
+    [HttpGet("{id:guid}")]
+    public async Task<ActionResult<LossDto>> Get(Guid id, CancellationToken ct)
+    {
+        var dto = await GetInternal(id, ct);
+        return dto is null ? NotFound() : Ok(dto);
+    }
+
+    [HttpPost, RequiresPermission("LossEdit")]
+    public async Task<ActionResult<LossDto>> Create([FromBody] LossInput input, CancellationToken ct)
+    {
+        if (RequiredGuid.FirstMissing(
+                (nameof(input.StoreId), input.StoreId),
+                (nameof(input.CurrencyId), input.CurrencyId)) is { } missing)
+            return BadRequest(new { error = $"Поле {missing} обязательно.", field = missing });
+        if (input.Lines is null || input.Lines.Count == 0)
+            return BadRequest(new { error = "Списание должно содержать хотя бы одну позицию." });
+
+        var number = await GenerateNumberAsync(input.Date, ct);
+        var loss = new Loss
+        {
+            Number = number,
+            Date = input.Date,
+            Status = LossStatus.Draft,
+            StoreId = input.StoreId,
+            CurrencyId = input.CurrencyId,
+            Reason = input.Reason,
+            Notes = input.Notes,
+        };
+        var order = 0;
+        foreach (var l in input.Lines)
+        {
+            loss.Lines.Add(new LossLine
+            {
+                ProductId = l.ProductId,
+                Quantity = l.Quantity,
+                UnitCost = l.UnitCost,
+                LineTotal = l.Quantity * l.UnitCost,
+                SortOrder = order++,
+            });
+        }
+        loss.Total = loss.Lines.Sum(x => x.LineTotal);
+
+        _db.Losses.Add(loss);
+        if (await SaveOrFkErrorAsync(ct) is { } err) return err;
+        var dto = await GetInternal(loss.Id, ct);
+        return CreatedAtAction(nameof(Get), new { id = loss.Id }, dto);
+    }
+
+    private async Task<ActionResult?> SaveOrFkErrorAsync(CancellationToken ct)
+    {
+        try
+        {
+            await _db.SaveChangesAsync(ct);
+            return null;
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is Npgsql.PostgresException pg && pg.SqlState == "23503")
+        {
+            var name = pg.ConstraintName ?? "";
+            string field = name.Contains("Store") ? "storeId"
+                         : name.Contains("Currency") ? "currencyId"
+                         : name.Contains("Product") ? "productId"
+                         : "(unknown)";
+            return BadRequest(new { error = $"Связанная запись не найдена: {field}.", field, constraint = name });
+        }
+    }
+
+    [HttpPut("{id:guid}"), RequiresPermission("LossEdit")]
+    public async Task<IActionResult> Update(Guid id, [FromBody] LossInput input, CancellationToken ct)
+    {
+        if (RequiredGuid.FirstMissing(
+                (nameof(input.StoreId), input.StoreId),
+                (nameof(input.CurrencyId), input.CurrencyId)) is { } missing)
+            return BadRequest(new { error = $"Поле {missing} обязательно.", field = missing });
+        if (input.Lines is null || input.Lines.Count == 0)
+            return BadRequest(new { error = "Списание должно содержать хотя бы одну позицию." });
+        var loss = await _db.Losses.Include(l => l.Lines).FirstOrDefaultAsync(l => l.Id == id, ct);
+        if (loss is null) return NotFound();
+        if (loss.Status != LossStatus.Draft)
+            return Conflict(new { error = "Только черновик может быть изменён. Сначала отмени проведение." });
+
+        loss.Date = input.Date;
+        loss.StoreId = input.StoreId;
+        loss.CurrencyId = input.CurrencyId;
+        loss.Reason = input.Reason;
+        loss.Notes = input.Notes;
+
+        _db.LossLines.RemoveRange(loss.Lines);
+        loss.Lines.Clear();
+        var order = 0;
+        foreach (var l in input.Lines)
+        {
+            loss.Lines.Add(new LossLine
+            {
+                LossId = loss.Id,
+                ProductId = l.ProductId,
+                Quantity = l.Quantity,
+                UnitCost = l.UnitCost,
+                LineTotal = l.Quantity * l.UnitCost,
+                SortOrder = order++,
+            });
+        }
+        loss.Total = loss.Lines.Sum(x => x.LineTotal);
+
+        if (await SaveOrFkErrorAsync(ct) is { } err) return err;
+        return NoContent();
+    }
+
+    [HttpDelete("{id:guid}"), RequiresPermission("LossEdit")]
+    public async Task<IActionResult> Delete(Guid id, CancellationToken ct)
+    {
+        var loss = await _db.Losses.FirstOrDefaultAsync(l => l.Id == id, ct);
+        if (loss is null) return NotFound();
+        if (loss.Status != LossStatus.Draft)
+            return Conflict(new { error = "Нельзя удалить проведённый документ. Сначала отмени проведение." });
+        _db.Losses.Remove(loss);
+        await _db.SaveChangesAsync(ct);
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/post"), RequiresPermission("LossEdit")]
+    public async Task<IActionResult> Post(Guid id, CancellationToken ct)
+    {
+        var loss = await _db.Losses.Include(l => l.Lines).FirstOrDefaultAsync(l => l.Id == id, ct);
+        if (loss is null) return NotFound();
+        if (loss.Status == LossStatus.Posted) return Conflict(new { error = "Документ уже проведён." });
+        if (loss.Lines.Count == 0) return BadRequest(new { error = "Нельзя провести документ без строк." });
+
+        // Защита от ухода stock в минус.
+        var byProduct = loss.Lines.GroupBy(l => l.ProductId)
+            .Select(g => new { ProductId = g.Key, Quantity = g.Sum(x => x.Quantity) }).ToList();
+        var productIds = byProduct.Select(x => x.ProductId).ToList();
+        var stocks = await _db.Stocks
+            .Where(s => s.StoreId == loss.StoreId && productIds.Contains(s.ProductId))
+            .ToDictionaryAsync(s => s.ProductId, s => s.Quantity, ct);
+        var conflicts = new List<object>();
+        foreach (var r in byProduct)
+        {
+            stocks.TryGetValue(r.ProductId, out var available);
+            if (available < r.Quantity)
+            {
+                var name = await _db.Products.Where(p => p.Id == r.ProductId)
+                    .Select(p => p.Name).FirstOrDefaultAsync(ct);
+                conflicts.Add(new
+                {
+                    productId = r.ProductId,
+                    productName = name,
+                    writeOffQty = r.Quantity,
+                    available,
+                });
+            }
+        }
+        if (conflicts.Count > 0)
+        {
+            return Conflict(new
+            {
+                error = "Нельзя списать больше, чем есть в наличии.",
+                lines = conflicts,
+            });
+        }
+
+        await using var tx = await _db.Database.BeginTransactionAsync(
+            System.Data.IsolationLevel.Serializable, ct);
+        var now = DateTime.UtcNow;
+
+        foreach (var line in loss.Lines)
+        {
+            await _stock.ApplyMovementAsync(new StockMovementDraft(
+                ProductId: line.ProductId,
+                StoreId: loss.StoreId,
+                Quantity: -line.Quantity,
+                Type: MovementType.WriteOff,
+                DocumentType: "loss",
+                DocumentId: loss.Id,
+                DocumentNumber: loss.Number,
+                UnitCost: line.UnitCost,
+                OccurredAt: loss.Date,
+                Notes: $"reason={loss.Reason}"), ct);
+        }
+
+        loss.Status = LossStatus.Posted;
+        loss.PostedAt = now;
+        try
+        {
+            await _db.SaveChangesAsync(ct);
+            await tx.CommitAsync(ct);
+        }
+        catch (Exception ex) when (IsSerializationConflict(ex))
+        {
+            return Conflict(new { error = "Документ проводится параллельно другим запросом. Повторите попытку." });
+        }
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/unpost"), RequiresPermission("LossEdit")]
+    public async Task<IActionResult> Unpost(Guid id, CancellationToken ct)
+    {
+        var loss = await _db.Losses.Include(l => l.Lines).FirstOrDefaultAsync(l => l.Id == id, ct);
+        if (loss is null) return NotFound();
+        if (loss.Status != LossStatus.Posted) return Conflict(new { error = "Документ не проведён." });
+
+        // Reverse: возвращаем товар обратно — остаток только увеличится, проверки на минус не нужно.
+        foreach (var line in loss.Lines)
+        {
+            await _stock.ApplyMovementAsync(new StockMovementDraft(
+                ProductId: line.ProductId,
+                StoreId: loss.StoreId,
+                Quantity: line.Quantity,
+                Type: MovementType.WriteOff,
+                DocumentType: "loss-reversal",
+                DocumentId: loss.Id,
+                DocumentNumber: loss.Number,
+                UnitCost: line.UnitCost,
+                OccurredAt: DateTime.UtcNow,
+                Notes: $"Отмена проведения документа {loss.Number}"), ct);
+        }
+
+        loss.Status = LossStatus.Draft;
+        loss.PostedAt = null;
+        await _db.SaveChangesAsync(ct);
+        return NoContent();
+    }
+
+    private static bool IsSerializationConflict(Exception ex)
+    {
+        for (Exception? e = ex; e is not null; e = e.InnerException)
+        {
+            if (e is System.Data.Common.DbException { SqlState: "40001" or "40P01" })
+                return true;
+        }
+        return false;
+    }
+
+    private async Task<string> GenerateNumberAsync(DateTime date, CancellationToken ct)
+    {
+        var year = date.Year;
+        var prefix = $"С-{year}-";
+        var lastNumber = await _db.Losses
+            .Where(l => l.Number.StartsWith(prefix))
+            .OrderByDescending(l => l.Number)
+            .Select(l => l.Number)
+            .FirstOrDefaultAsync(ct);
+
+        var seq = 1;
+        if (lastNumber is not null && int.TryParse(lastNumber[prefix.Length..], out var last))
+            seq = last + 1;
+        return $"{prefix}{seq:D6}";
+    }
+
+    private async Task<LossDto?> GetInternal(Guid id, CancellationToken ct)
+    {
+        var row = await (from l in _db.Losses.AsNoTracking()
+                         join st in _db.Stores on l.StoreId equals st.Id
+                         join cu in _db.Currencies on l.CurrencyId equals cu.Id
+                         where l.Id == id
+                         select new { l, st, cu }).FirstOrDefaultAsync(ct);
+        if (row is null) return null;
+
+        var lines = await (from l in _db.LossLines.AsNoTracking()
+                           join p in _db.Products on l.ProductId equals p.Id
+                           join u in _db.UnitsOfMeasure on p.UnitOfMeasureId equals u.Id
+                           where l.LossId == id
+                           orderby l.SortOrder
+                           select new LossLineDto(
+                               l.Id, l.ProductId, p.Name, p.Article,
+                               u.Name,
+                               l.Quantity, l.UnitCost, l.LineTotal, l.SortOrder,
+                               _db.Stocks.Where(s => s.ProductId == l.ProductId && s.StoreId == row.l.StoreId)
+                                   .Select(s => (decimal?)s.Quantity).FirstOrDefault()))
+                          .ToListAsync(ct);
+
+        return new LossDto(
+            row.l.Id, row.l.Number, row.l.Date, row.l.Status, row.l.Reason,
+            row.st.Id, row.st.Name,
+            row.cu.Id, row.cu.Code,
+            row.l.Notes,
+            row.l.Total, row.l.PostedAt,
+            lines);
+    }
+}

src/food-market.domain/Inventory/Loss.cs

@@ -0,0 +1,72 @@
+using foodmarket.Domain.Catalog;
+using foodmarket.Domain.Common;
+
+namespace foodmarket.Domain.Inventory;
+
+public enum LossStatus
+{
+    Draft = 0,
+    Posted = 1,
+}
+
+/// <summary>Причина списания. Из этого классификатора строятся ABC/XYZ-отчёты
+/// и фискальная отчётность (порча/просрочка) в KZ. Не строй наценочную логику
+/// поверх этих значений — используй ровно как business reason.</summary>
+public enum LossReason
+{
+    /// <summary>Брак (производственный/транспортный).</summary>
+    Defect = 0,
+    /// <summary>Просрочка / истёк срок годности.</summary>
+    Expired = 1,
+    /// <summary>Повреждение (механическое, при хранении/перевозке).</summary>
+    Damage = 2,
+    /// <summary>Недостача (выявлена инвентаризацией; для оформления свыше — отдельный документ инвентаризации).</summary>
+    Shortage = 3,
+    /// <summary>Прочая причина (в комментарии).</summary>
+    Other = 99,
+}
+
+/// <summary>Документ списания со склада: брак, просрочка, недостача, повреждение.
+/// При проведении создаёт <see cref="StockMovement"/> с типом
+/// <see cref="MovementType.WriteOff"/> и отрицательным Quantity.</summary>
+public class Loss : TenantEntity
+{
+    public string Number { get; set; } = "";
+    public DateTime Date { get; set; } = DateTime.UtcNow;
+    public LossStatus Status { get; set; } = LossStatus.Draft;
+
+    public Guid StoreId { get; set; }
+    public Store Store { get; set; } = null!;
+
+    public Guid CurrencyId { get; set; }
+    public Currency Currency { get; set; } = null!;
+
+    public LossReason Reason { get; set; } = LossReason.Other;
+
+    public string? Notes { get; set; }
+
+    /// <summary>Сумма по строкам = Σ Quantity·UnitCost. Балансовая стоимость списания.</summary>
+    public decimal Total { get; set; }
+
+    public DateTime? PostedAt { get; set; }
+    public Guid? PostedByUserId { get; set; }
+
+    public ICollection<LossLine> Lines { get; set; } = new List<LossLine>();
+}
+
+public class LossLine : TenantEntity
+{
+    public Guid LossId { get; set; }
+    public Loss Loss { get; set; } = null!;
+
+    public Guid ProductId { get; set; }
+    public Product Product { get; set; } = null!;
+
+    public decimal Quantity { get; set; }
+    /// <summary>Балансовая цена единицы (снимок Product.Cost на момент создания строки;
+    /// можно переопределить). Используется в Total и в отчётности.</summary>
+    public decimal UnitCost { get; set; }
+    public decimal LineTotal { get; set; }
+
+    public int SortOrder { get; set; }
+}

src/food-market.infrastructure/Persistence/AppDbContext.cs

@@ -47,6 +47,9 @@ public AppDbContext(DbContextOptions<AppDbContext> options, ITenantContext tenan
     public DbSet<Enter> Enters => Set<Enter>();
     public DbSet<EnterLine> EnterLines => Set<EnterLine>();
 
+    public DbSet<Loss> Losses => Set<Loss>();
+    public DbSet<LossLine> LossLines => Set<LossLine>();
+
     public DbSet<RetailSale> RetailSales => Set<RetailSale>();
     public DbSet<RetailSaleLine> RetailSaleLines => Set<RetailSaleLine>();
 

src/food-market.infrastructure/Persistence/Configurations/InventoryConfigurations.cs

@@ -37,5 +37,35 @@ public static void ConfigureInventory(this ModelBuilder b)
             e.HasIndex(x => new { x.OrganizationId, x.StoreId, x.OccurredAt });
             e.HasIndex(x => new { x.DocumentType, x.DocumentId });
         });
+
+        b.Entity<Loss>(e =>
+        {
+            e.ToTable("losses");
+            e.Property(x => x.Number).HasMaxLength(50).IsRequired();
+            e.Property(x => x.Notes).HasMaxLength(1000);
+            e.Property(x => x.Total).HasPrecision(18, 4);
+
+            e.HasOne(x => x.Store).WithMany().HasForeignKey(x => x.StoreId).OnDelete(DeleteBehavior.Restrict);
+            e.HasOne(x => x.Currency).WithMany().HasForeignKey(x => x.CurrencyId).OnDelete(DeleteBehavior.Restrict);
+
+            e.HasMany(x => x.Lines).WithOne(l => l.Loss).HasForeignKey(l => l.LossId).OnDelete(DeleteBehavior.Cascade);
+
+            e.HasIndex(x => new { x.OrganizationId, x.Number }).IsUnique();
+            e.HasIndex(x => new { x.OrganizationId, x.Date });
+            e.HasIndex(x => new { x.OrganizationId, x.Status });
+            e.HasIndex(x => new { x.OrganizationId, x.Reason });
+        });
+
+        b.Entity<LossLine>(e =>
+        {
+            e.ToTable("loss_lines");
+            e.Property(x => x.Quantity).HasPrecision(18, 4);
+            e.Property(x => x.UnitCost).HasPrecision(18, 4);
+            e.Property(x => x.LineTotal).HasPrecision(18, 4);
+
+            e.HasOne(x => x.Product).WithMany().HasForeignKey(x => x.ProductId).OnDelete(DeleteBehavior.Restrict);
+
+            e.HasIndex(x => new { x.OrganizationId, x.ProductId });
+        });
     }
 }

src/food-market.infrastructure/Persistence/Migrations/20260528010000_Phase6b_Losses.cs

@@ -0,0 +1,79 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using foodmarket.Infrastructure.Persistence;
+
+#nullable disable
+
+namespace foodmarket.Infrastructure.Persistence.Migrations
+{
+    /// <summary>Phase6b — списание (Loss).
+    ///
+    /// Документ списания со склада с указанием причины (LossReason): брак,
+    /// просрочка, повреждение, недостача, прочее. При проведении создаёт
+    /// <c>stock_movements</c> с типом <c>WriteOff</c> и отрицательным
+    /// Quantity.
+    ///
+    /// Шаги идемпотентны через IF NOT EXISTS.</summary>
+    [DbContext(typeof(AppDbContext))]
+    [Migration("20260528010000_Phase6b_Losses")]
+    public partial class Phase6b_Losses : Migration
+    {
+        protected override void Up(MigrationBuilder b)
+        {
+            b.Sql(@"
+                CREATE TABLE IF NOT EXISTS public.losses (
+                    ""Id""               uuid PRIMARY KEY,
+                    ""OrganizationId""   uuid NOT NULL,
+                    ""Number""           varchar(50) NOT NULL,
+                    ""Date""             timestamp with time zone NOT NULL,
+                    ""Status""           integer NOT NULL,
+                    ""StoreId""          uuid NOT NULL,
+                    ""CurrencyId""       uuid NOT NULL,
+                    ""Reason""           integer NOT NULL,
+                    ""Notes""            varchar(1000),
+                    ""Total""            numeric(18,4) NOT NULL,
+                    ""PostedAt""         timestamp with time zone,
+                    ""PostedByUserId""   uuid,
+                    ""CreatedAt""        timestamp with time zone NOT NULL,
+                    ""UpdatedAt""        timestamp with time zone,
+                    CONSTRAINT ""FK_losses_stores_StoreId"" FOREIGN KEY (""StoreId"") REFERENCES public.stores(""Id"") ON DELETE RESTRICT,
+                    CONSTRAINT ""FK_losses_currencies_CurrencyId"" FOREIGN KEY (""CurrencyId"") REFERENCES public.currencies(""Id"") ON DELETE RESTRICT
+                );
+
+                CREATE UNIQUE INDEX IF NOT EXISTS ""IX_losses_OrganizationId_Number"" ON public.losses (""OrganizationId"", ""Number"");
+                CREATE INDEX IF NOT EXISTS ""IX_losses_OrganizationId_Date"" ON public.losses (""OrganizationId"", ""Date"");
+                CREATE INDEX IF NOT EXISTS ""IX_losses_OrganizationId_Status"" ON public.losses (""OrganizationId"", ""Status"");
+                CREATE INDEX IF NOT EXISTS ""IX_losses_OrganizationId_Reason"" ON public.losses (""OrganizationId"", ""Reason"");
+                CREATE INDEX IF NOT EXISTS ""IX_losses_StoreId"" ON public.losses (""StoreId"");
+                CREATE INDEX IF NOT EXISTS ""IX_losses_CurrencyId"" ON public.losses (""CurrencyId"");
+
+                CREATE TABLE IF NOT EXISTS public.loss_lines (
+                    ""Id""               uuid PRIMARY KEY,
+                    ""OrganizationId""   uuid NOT NULL,
+                    ""LossId""           uuid NOT NULL,
+                    ""ProductId""        uuid NOT NULL,
+                    ""Quantity""         numeric(18,4) NOT NULL,
+                    ""UnitCost""         numeric(18,4) NOT NULL,
+                    ""LineTotal""        numeric(18,4) NOT NULL,
+                    ""SortOrder""        integer NOT NULL,
+                    ""CreatedAt""        timestamp with time zone NOT NULL,
+                    ""UpdatedAt""        timestamp with time zone,
+                    CONSTRAINT ""FK_loss_lines_losses_LossId"" FOREIGN KEY (""LossId"") REFERENCES public.losses(""Id"") ON DELETE CASCADE,
+                    CONSTRAINT ""FK_loss_lines_products_ProductId"" FOREIGN KEY (""ProductId"") REFERENCES public.products(""Id"") ON DELETE RESTRICT
+                );
+
+                CREATE INDEX IF NOT EXISTS ""IX_loss_lines_LossId"" ON public.loss_lines (""LossId"");
+                CREATE INDEX IF NOT EXISTS ""IX_loss_lines_ProductId"" ON public.loss_lines (""ProductId"");
+                CREATE INDEX IF NOT EXISTS ""IX_loss_lines_OrganizationId_ProductId"" ON public.loss_lines (""OrganizationId"", ""ProductId"");
+            ");
+        }
+
+        protected override void Down(MigrationBuilder b)
+        {
+            b.Sql(@"
+                DROP TABLE IF EXISTS public.loss_lines;
+                DROP TABLE IF EXISTS public.losses;
+            ");
+        }
+    }
+}

src/food-market.web/src/App.tsx

@@ -30,6 +30,8 @@ import { SuppliesPage } from '@/pages/SuppliesPage'
 import { SupplyEditPage } from '@/pages/SupplyEditPage'
 import { EntersPage } from '@/pages/EntersPage'
 import { EnterEditPage } from '@/pages/EnterEditPage'
+import { LossesPage } from '@/pages/LossesPage'
+import { LossEditPage } from '@/pages/LossEditPage'
 import { RetailSalesPage } from '@/pages/RetailSalesPage'
 import { RetailSaleEditPage } from '@/pages/RetailSaleEditPage'
 import { AppLayout } from '@/components/AppLayout'
@@ -105,6 +107,9 @@ export default function App() {
               <Route path="/inventory/enters" element={<EntersPage />} />
               <Route path="/inventory/enters/new" element={<EnterEditPage />} />
               <Route path="/inventory/enters/:id" element={<EnterEditPage />} />
+              <Route path="/inventory/losses" element={<LossesPage />} />
+              <Route path="/inventory/losses/new" element={<LossEditPage />} />
+              <Route path="/inventory/losses/:id" element={<LossEditPage />} />
               <Route path="/sales/retail" element={<RetailSalesPage />} />
               <Route path="/sales/retail/new" element={<RetailSaleEditPage />} />
               <Route path="/sales/retail/:id" element={<RetailSaleEditPage />} />

src/food-market.web/src/components/AppLayout.tsx

@@ -7,7 +7,7 @@ import { cn } from '@/lib/utils'
 import {
   LayoutDashboard, Package, FolderTree, Ruler, Tag,
   Users, Warehouse, Store as StoreIcon, LogOut, Download, UserCog, Shield, ShieldCheck,
-  Boxes, History, TruckIcon, ShoppingCart, Settings, Menu, X, PackagePlus,
+  Boxes, History, TruckIcon, ShoppingCart, Settings, Menu, X, PackagePlus, PackageMinus,
 } from 'lucide-react'
 import { Logo } from './Logo'
 import { SuperAdminAsOrgBanner } from './SuperAdminAsOrgBanner'
@@ -86,6 +86,7 @@ function buildNav(roles: string[]): NavSection[] {
     if (isAdmin || isStorekeeper) {
       stock.push({ to: '/inventory/movements', icon: History, label: 'Движения' })
       stock.push({ to: '/inventory/enters', icon: PackagePlus, label: 'Оприходования' })
+      stock.push({ to: '/inventory/losses', icon: PackageMinus, label: 'Списания' })
     }
     sections.push({ group: 'Остатки', items: stock })
   }

src/food-market.web/src/lib/types.ts

@@ -137,6 +137,42 @@ export interface EnterDto {
   lines: EnterLineDto[];
 }
 
+export const LossStatus = { Draft: 0, Posted: 1 } as const
+export type LossStatus = (typeof LossStatus)[keyof typeof LossStatus]
+
+export const LossReason = { Defect: 0, Expired: 1, Damage: 2, Shortage: 3, Other: 99 } as const
+export type LossReason = (typeof LossReason)[keyof typeof LossReason]
+export const lossReasonLabel: Record<LossReason, string> = {
+  [LossReason.Defect]: 'Брак',
+  [LossReason.Expired]: 'Просрочка',
+  [LossReason.Damage]: 'Повреждение',
+  [LossReason.Shortage]: 'Недостача',
+  [LossReason.Other]: 'Прочее',
+}
+
+export interface LossListRow {
+  id: string; number: string; date: string; status: LossStatus; reason: LossReason;
+  storeId: string; storeName: string;
+  currencyId: string; currencyCode: string;
+  total: number; lineCount: number; postedAt: string | null;
+}
+
+export interface LossLineDto {
+  id: string | null; productId: string;
+  productName: string | null; productArticle: string | null; unitSymbol: string | null;
+  quantity: number; unitCost: number; lineTotal: number; sortOrder: number;
+  stockAtStore: number | null;
+}
+
+export interface LossDto {
+  id: string; number: string; date: string; status: LossStatus; reason: LossReason;
+  storeId: string; storeName: string;
+  currencyId: string; currencyCode: string;
+  notes: string | null;
+  total: number; postedAt: string | null;
+  lines: LossLineDto[];
+}
+
 export const RetailSaleStatus = { Draft: 0, Posted: 1 } as const
 export type RetailSaleStatus = (typeof RetailSaleStatus)[keyof typeof RetailSaleStatus]
 

src/food-market.web/src/pages/LossEditPage.tsx

@@ -0,0 +1,362 @@
+import { useState, useEffect, type FormEvent } from 'react'
+import { useNavigate, useParams, Link } from 'react-router-dom'
+import { useQuery, useQueryClient, useMutation } from '@tanstack/react-query'
+import { ArrowLeft, Plus, Trash2, Save, CheckCircle } from 'lucide-react'
+import { api } from '@/lib/api'
+import { Button } from '@/components/Button'
+import { Field, TextArea, Select, MoneyInput, NumberInput, Checkbox } from '@/components/Field'
+import { DateField } from '@/components/DateField'
+import { ProductPicker } from '@/components/ProductPicker'
+import { useStores, useCurrencies } from '@/lib/useLookups'
+import { useOrgSettings } from '@/lib/useOrgSettings'
+import { LossStatus, LossReason, lossReasonLabel, type LossDto, type Product } from '@/lib/types'
+
+interface LineRow {
+  productId: string
+  productName: string
+  productArticle: string | null
+  unitSymbol: string | null
+  quantity: number
+  unitCost: number
+  stockAtStore: number | null
+}
+
+interface Form {
+  date: string
+  storeId: string
+  currencyId: string
+  reason: LossReason
+  notes: string
+  lines: LineRow[]
+}
+
+const todayIso = () => {
+  const d = new Date()
+  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}-${String(d.getDate()).padStart(2, '0')}`
+}
+
+const emptyForm: Form = {
+  date: todayIso(), storeId: '', currencyId: '', reason: LossReason.Other, notes: '', lines: [],
+}
+
+export function LossEditPage() {
+  const { id } = useParams<{ id: string }>()
+  const isNew = !id || id === 'new'
+  const navigate = useNavigate()
+  const qc = useQueryClient()
+
+  const stores = useStores()
+  const currencies = useCurrencies()
+  const org = useOrgSettings()
+
+  const [form, setForm] = useState<Form>(emptyForm)
+  const [pickerOpen, setPickerOpen] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  const existing = useQuery({
+    queryKey: ['/api/inventory/losses', id],
+    queryFn: async () => (await api.get<LossDto>(`/api/inventory/losses/${id}`)).data,
+    enabled: !isNew,
+  })
+
+  useEffect(() => {
+    if (!isNew && existing.data) {
+      const s = existing.data
+      setForm({
+        date: s.date.slice(0, 10),
+        storeId: s.storeId,
+        currencyId: s.currencyId,
+        reason: s.reason,
+        notes: s.notes ?? '',
+        lines: s.lines.map((l) => ({
+          productId: l.productId,
+          productName: l.productName ?? '',
+          productArticle: l.productArticle,
+          unitSymbol: l.unitSymbol,
+          quantity: l.quantity,
+          unitCost: l.unitCost,
+          stockAtStore: l.stockAtStore,
+        })),
+      })
+    }
+  }, [isNew, existing.data])
+
+  useEffect(() => {
+    if (isNew) {
+      if (!form.storeId && stores.data?.length) {
+        const main = stores.data.find((s) => s.isMain) ?? stores.data[0]
+        setForm((f) => ({ ...f, storeId: main.id }))
+      }
+      if (!form.currencyId && currencies.data?.length) {
+        const def = org.data?.defaultCurrencyId
+          ? currencies.data.find((c) => c.id === org.data!.defaultCurrencyId)
+          : currencies.data.find((c) => c.code === 'KZT')
+        if (def) setForm((f) => ({ ...f, currencyId: def.id }))
+      }
+    }
+  }, [isNew, stores.data, currencies.data, org.data?.defaultCurrencyId, form.storeId, form.currencyId])
+
+  const isDraft = isNew || existing.data?.status === LossStatus.Draft
+  const isPosted = existing.data?.status === LossStatus.Posted
+
+  const lineTotal = (l: LineRow) => l.quantity * l.unitCost
+  const grandTotal = form.lines.reduce((s, l) => s + lineTotal(l), 0)
+
+  const save = useMutation({
+    mutationFn: async () => {
+      const payload = {
+        date: new Date(form.date).toISOString(),
+        storeId: form.storeId,
+        currencyId: form.currencyId,
+        reason: form.reason,
+        notes: form.notes || null,
+        lines: form.lines.map((l) => ({
+          productId: l.productId, quantity: l.quantity, unitCost: l.unitCost,
+        })),
+      }
+      if (isNew) return (await api.post<LossDto>('/api/inventory/losses', payload)).data
+      await api.put(`/api/inventory/losses/${id}`, payload)
+      return null
+    },
+    onSuccess: (created) => {
+      qc.invalidateQueries({ queryKey: ['/api/inventory/losses'] })
+      navigate(created ? `/inventory/losses/${created.id}` : `/inventory/losses/${id}`)
+    },
+    onError: (e: Error) => setError(e.message),
+  })
+
+  const post = useMutation({
+    mutationFn: async () => { await api.post(`/api/inventory/losses/${id}/post`) },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['/api/inventory/losses'] })
+      qc.invalidateQueries({ queryKey: ['/api/inventory/stock'] })
+      qc.invalidateQueries({ queryKey: ['/api/inventory/movements'] })
+      existing.refetch()
+    },
+    onError: (e: Error) => {
+      const msg = (e as { response?: { data?: { error?: string } } }).response?.data?.error ?? e.message
+      setError(msg)
+    },
+  })
+
+  const unpost = useMutation({
+    mutationFn: async () => { await api.post(`/api/inventory/losses/${id}/unpost`) },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['/api/inventory/losses'] })
+      qc.invalidateQueries({ queryKey: ['/api/inventory/stock'] })
+      qc.invalidateQueries({ queryKey: ['/api/inventory/movements'] })
+      existing.refetch()
+    },
+    onError: (e: Error) => setError(e.message),
+  })
+
+  const remove = useMutation({
+    mutationFn: async () => { await api.delete(`/api/inventory/losses/${id}`) },
+    onSuccess: () => navigate('/inventory/losses'),
+    onError: (e: Error) => setError(e.message),
+  })
+
+  const onSubmit = (e: FormEvent) => { e.preventDefault(); save.mutate() }
+
+  const addLineFromProduct = (p: Product) => {
+    setForm({
+      ...form,
+      lines: [...form.lines, {
+        productId: p.id,
+        productName: p.name,
+        productArticle: p.article,
+        unitSymbol: p.unitName,
+        quantity: 1,
+        unitCost: p.cost ?? 0,
+        stockAtStore: null,
+      }],
+    })
+  }
+  const updateLine = (i: number, patch: Partial<LineRow>) =>
+    setForm({ ...form, lines: form.lines.map((l, ix) => ix === i ? { ...l, ...patch } : l) })
+  const removeLine = (i: number) =>
+    setForm({ ...form, lines: form.lines.filter((_, ix) => ix !== i) })
+
+  const canSave = !!form.date && !!form.storeId && !!form.currencyId
+    && form.lines.length > 0 && isDraft
+
+  const fractional = org.data?.allowFractionalPrices ?? false
+  const moneyFmt = fractional
+    ? { minimumFractionDigits: 2, maximumFractionDigits: 2 }
+    : { maximumFractionDigits: 0 }
+
+  return (
+    <form onSubmit={onSubmit} className="flex flex-col h-full">
+      <div className="flex items-center justify-between gap-4 px-6 py-3 border-b border-slate-200 dark:border-slate-800 bg-white dark:bg-slate-900">
+        <div className="flex items-center gap-3 min-w-0">
+          <Link to="/inventory/losses" className="text-slate-400 hover:text-slate-700 dark:hover:text-slate-200 flex-shrink-0">
+            <ArrowLeft className="w-5 h-5" />
+          </Link>
+          <div className="min-w-0">
+            <h1 className="text-base font-semibold text-slate-900 dark:text-slate-100 truncate">
+              {isNew ? 'Новое списание' : existing.data?.number ?? 'Списание'}
+            </h1>
+            <p className="text-xs text-slate-500">
+              {isPosted
+                ? <span className="text-green-700 inline-flex items-center gap-1"><CheckCircle className="w-3 h-3" /> Проведён {existing.data?.postedAt ? new Date(existing.data.postedAt).toLocaleString('ru') : ''}</span>
+                : 'Черновик — товар не списан, пока не проведёшь'}
+            </p>
+          </div>
+        </div>
+        <div className="flex gap-3 flex-shrink-0 items-center">
+          {isDraft && !isNew && (
+            <Button type="button" variant="danger" size="sm" onClick={() => { if (confirm('Удалить черновик?')) remove.mutate() }}>
+              <Trash2 className="w-4 h-4" /> Удалить
+            </Button>
+          )}
+          {isDraft && (
+            <Button type="submit" disabled={!canSave || save.isPending}>
+              <Save className="w-4 h-4" /> {save.isPending ? 'Сохраняю…' : 'Сохранить'}
+            </Button>
+          )}
+        </div>
+      </div>
+
+      <div className="flex-1 overflow-auto">
+        <div className="max-w-5xl mx-auto p-3 sm:p-6 space-y-4">
+          {error && (
+            <div className="p-3 rounded-md bg-red-50 text-red-700 text-sm border border-red-200">{error}</div>
+          )}
+
+          <section className="bg-white dark:bg-slate-900 rounded-lg border border-slate-200 dark:border-slate-800 p-4">
+            <div className="grid grid-cols-1 md:grid-cols-3 gap-x-4 gap-y-3">
+              <Field label="Дата *">
+                <DateField required value={form.date || null} disabled={isPosted}
+                  onChange={(iso) => setForm({ ...form, date: iso ?? '' })} />
+              </Field>
+              <Field label="Склад *">
+                <Select value={form.storeId} disabled={isPosted}
+                  onChange={(e) => setForm({ ...form, storeId: e.target.value })}>
+                  <option value="">—</option>
+                  {stores.data?.map((s) => <option key={s.id} value={s.id}>{s.name}</option>)}
+                </Select>
+              </Field>
+              <Field label="Причина *">
+                <Select value={String(form.reason)} disabled={isPosted}
+                  onChange={(e) => setForm({ ...form, reason: Number(e.target.value) as LossReason })}>
+                  {Object.entries(lossReasonLabel).map(([v, lbl]) => (
+                    <option key={v} value={v}>{lbl}</option>
+                  ))}
+                </Select>
+              </Field>
+              {org.data?.multiCurrencyEnabled && (
+                <Field label="Валюта *">
+                  <Select value={form.currencyId} disabled={isPosted}
+                    onChange={(e) => setForm({ ...form, currencyId: e.target.value })}>
+                    <option value="">—</option>
+                    {currencies.data?.map((c) => <option key={c.id} value={c.id}>{c.code}</option>)}
+                  </Select>
+                </Field>
+              )}
+              <Field label="Комментарий" className="md:col-span-3">
+                <TextArea rows={2} value={form.notes} disabled={isPosted}
+                  onChange={(e) => setForm({ ...form, notes: e.target.value })}
+                  placeholder="Детали (партия, накладная, акт)…" />
+              </Field>
+            </div>
+
+            {!isNew && (
+              <div className="mt-4 pt-4 border-t border-slate-100 dark:border-slate-800">
+                <Checkbox
+                  label="Проведено"
+                  checked={isPosted}
+                  disabled={post.isPending || unpost.isPending || form.lines.length === 0}
+                  onChange={(v) => {
+                    if (v) {
+                      if (confirm('Провести? Товар будет списан со склада.')) post.mutate()
+                    } else {
+                      if (confirm('Снять проведение? Списанный товар вернётся на остаток.')) unpost.mutate()
+                    }
+                  }}
+                />
+              </div>
+            )}
+          </section>
+
+          <section className="bg-white dark:bg-slate-900 rounded-lg border border-slate-200 dark:border-slate-800 p-4">
+            <div className="flex items-center justify-between mb-3">
+              <h2 className="font-medium text-slate-900 dark:text-slate-100">Позиции</h2>
+              {!isPosted && (
+                <Button type="button" variant="secondary" size="sm" onClick={() => setPickerOpen(true)}>
+                  <Plus className="w-3.5 h-3.5" /> Добавить из справочника
+                </Button>
+              )}
+            </div>
+
+            {form.lines.length === 0 ? (
+              <div className="text-sm text-slate-500 py-6 text-center">Нет позиций.</div>
+            ) : (
+              <div className="overflow-x-auto">
+                <table className="w-full text-sm">
+                  <thead className="text-left">
+                    <tr className="border-b border-slate-200 dark:border-slate-700">
+                      <th className="py-2 pr-3 font-medium text-xs uppercase text-slate-500">Товар</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[80px]">Ед.</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[100px] text-right">Остаток</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[120px] text-right">Списать</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[140px] text-right">Цена ед.</th>
+                      <th className="py-2 px-3 font-medium text-xs uppercase text-slate-500 w-[140px] text-right">Сумма</th>
+                      <th className="w-8"></th>
+                    </tr>
+                  </thead>
+                  <tbody>
+                    {form.lines.map((l, i) => (
+                      <tr key={i} className="border-b border-slate-100 dark:border-slate-800">
+                        <td className="py-2 pr-3">
+                          <div className="font-medium text-slate-800 dark:text-slate-100">{l.productName || '(без названия)'}</div>
+                          {l.productArticle && <div className="text-xs text-slate-500">{l.productArticle}</div>}
+                        </td>
+                        <td className="py-2 px-3 text-slate-500">{l.unitSymbol ?? '—'}</td>
+                        <td className="py-2 px-3 text-right font-mono text-slate-500">
+                          {l.stockAtStore != null ? l.stockAtStore.toLocaleString('ru') : '—'}
+                        </td>
+                        <td className="py-2 px-3 text-right">
+                          <NumberInput value={l.quantity} disabled={isPosted}
+                            onChange={(v) => updateLine(i, { quantity: v ?? 0 })} />
+                        </td>
+                        <td className="py-2 px-3 text-right">
+                          <MoneyInput value={l.unitCost} disabled={isPosted}
+                            allowFractional={fractional}
+                            onChange={(v) => updateLine(i, { unitCost: v ?? 0 })} />
+                        </td>
+                        <td className="py-2 px-3 text-right font-mono">
+                          {lineTotal(l).toLocaleString('ru', moneyFmt)}
+                        </td>
+                        <td className="py-2 px-1">
+                          {!isPosted && (
+                            <button type="button" onClick={() => removeLine(i)}
+                              className="text-slate-400 hover:text-red-600">
+                              <Trash2 className="w-4 h-4" />
+                            </button>
+                          )}
+                        </td>
+                      </tr>
+                    ))}
+                    <tr className="font-medium">
+                      <td className="py-3 pr-3" colSpan={5}>Итого</td>
+                      <td className="py-3 px-3 text-right font-mono">
+                        {grandTotal.toLocaleString('ru', moneyFmt)} {existing.data?.currencyCode ?? ''}
+                      </td>
+                      <td />
+                    </tr>
+                  </tbody>
+                </table>
+              </div>
+            )}
+          </section>
+        </div>
+      </div>
+
+      <ProductPicker
+        open={pickerOpen}
+        onClose={() => setPickerOpen(false)}
+        onPick={(p) => { addLineFromProduct(p); setPickerOpen(false) }}
+      />
+    </form>
+  )
+}

src/food-market.web/src/pages/LossesPage.tsx

@@ -0,0 +1,64 @@
+import { Link, useNavigate } from 'react-router-dom'
+import { Plus } from 'lucide-react'
+import { ListPageShell } from '@/components/ListPageShell'
+import { DataTable } from '@/components/DataTable'
+import { Pagination } from '@/components/Pagination'
+import { SearchBar } from '@/components/SearchBar'
+import { Button } from '@/components/Button'
+import { useCatalogList } from '@/lib/useCatalog'
+import { useOrgSettings } from '@/lib/useOrgSettings'
+import { type LossListRow, LossStatus, lossReasonLabel } from '@/lib/types'
+
+const URL = '/api/inventory/losses'
+
+export function LossesPage() {
+  const navigate = useNavigate()
+  const { data, isLoading, page, setPage, search, setSearch, sortKey, sortOrder, setSort } = useCatalogList<LossListRow>(URL)
+  const org = useOrgSettings()
+  const fractional = org.data?.allowFractionalPrices ?? false
+  const moneyFmt = fractional
+    ? { minimumFractionDigits: 2, maximumFractionDigits: 2 }
+    : { maximumFractionDigits: 0 }
+
+  return (
+    <ListPageShell
+      title="Списания"
+      description={data ? `${data.total.toLocaleString('ru')} документов` : 'Брак, просрочка, повреждения, недостача.'}
+      actions={
+        <>
+          <SearchBar value={search} onChange={setSearch} placeholder="По номеру…" />
+          <Link to="/inventory/losses/new">
+            <Button><Plus className="w-4 h-4" /> Новое списание</Button>
+          </Link>
+        </>
+      }
+      footer={data && data.total > 0 && (
+        <Pagination page={page} pageSize={data.pageSize} total={data.total} onPageChange={setPage} />
+      )}
+    >
+      <DataTable
+        rows={data?.items ?? []}
+        isLoading={isLoading}
+        rowKey={(r) => r.id}
+        sortKey={sortKey}
+        sortOrder={sortOrder}
+        onSortChange={setSort}
+        onRowClick={(r) => navigate(`/inventory/losses/${r.id}`)}
+        columns={[
+          { header: '№', width: '160px', sortKey: 'number', cell: (r) => <span className="font-mono text-slate-600">{r.number}</span> },
+          { header: 'Дата', width: '120px', sortKey: 'date', cell: (r) => new Date(r.date).toLocaleDateString('ru') },
+          { header: 'Статус', width: '110px', sortKey: 'status', cell: (r) => (
+            r.status === LossStatus.Posted
+              ? <span className="text-xs px-2 py-0.5 rounded bg-green-50 text-green-700">Проведён</span>
+              : <span className="text-xs px-2 py-0.5 rounded bg-slate-100 text-slate-600">Черновик</span>
+          )},
+          { header: 'Причина', width: '140px', sortKey: 'reason', cell: (r) => lossReasonLabel[r.reason] ?? r.reason },
+          { header: 'Склад', sortKey: 'store', cell: (r) => r.storeName },
+          { header: 'Позиций', width: '90px', className: 'text-right', cell: (r) => r.lineCount },
+          { header: 'Сумма', width: '160px', className: 'text-right font-mono', sortKey: 'total', cell: (r) => `${r.total.toLocaleString('ru', moneyFmt)} ${r.currencyCode}` },
+        ]}
+        empty="Списаний пока нет."
+      />
+    </ListPageShell>
+  )
+}

tests/food-market.IntegrationTests/LossPostUnpostTests.cs

@@ -0,0 +1,117 @@
+using System.Net.Http.Json;
+using System.Text.Json;
+using FluentAssertions;
+using foodmarket.IntegrationTests.Support;
+using Xunit;
+
+namespace foodmarket.IntegrationTests;
+
+[Collection(ApiCollection.Name)]
+public class LossPostUnpostTests
+{
+    private readonly ApiFactory _factory;
+    public LossPostUnpostTests(ApiFactory factory) => _factory = factory;
+
+    private static string RandomBarcode()
+        => string.Concat(Enumerable.Range(0, 13).Select(_ => Random.Shared.Next(0, 10)));
+
+    /// <summary>Положить через Enter, потом списать, проверить остаток и обратимость.</summary>
+    [Fact]
+    public async Task Posting_loss_decrements_stock_unpost_restores()
+    {
+        var api = new ApiActor(_factory.CreateClient());
+        await api.SignupAndLoginAsync($"loss-{Guid.NewGuid():N}");
+        var refs = await api.LoadRefsAsync();
+        var productId = await api.CreateProductAsync(refs, $"Prod-{Guid.NewGuid():N}", 200m, RandomBarcode());
+
+        // Сначала оприходуем 10 шт чтобы было что списывать.
+        var enter = await api.Http.PostAsJsonAsync("/api/inventory/enters", new
+        {
+            date = DateTime.UtcNow, storeId = refs.StoreId, currencyId = refs.CurrencyId,
+            notes = "seed", lines = new[] { new { productId, quantity = 10m, unitCost = 50m } },
+        });
+        enter.EnsureSuccessStatusCode();
+        var enterId = (await enter.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+        (await api.Http.PostAsJsonAsync($"/api/inventory/enters/{enterId}/post", new { }))
+            .IsSuccessStatusCode.Should().BeTrue();
+        (await api.StockOfAsync(refs.StoreId, productId)).Should().Be(10m);
+
+        // Списываем 3 шт с причиной Expired.
+        var loss = await api.Http.PostAsJsonAsync("/api/inventory/losses", new
+        {
+            date = DateTime.UtcNow, storeId = refs.StoreId, currencyId = refs.CurrencyId,
+            reason = 1, // Expired
+            notes = "просрочка партии",
+            lines = new[] { new { productId, quantity = 3m, unitCost = 50m } },
+        });
+        loss.EnsureSuccessStatusCode();
+        var lossId = (await loss.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+
+        using var post = await api.Http.PostAsJsonAsync($"/api/inventory/losses/{lossId}/post", new { });
+        post.IsSuccessStatusCode.Should().BeTrue($"post вернул {(int)post.StatusCode}: {await post.Content.ReadAsStringAsync()}");
+        (await api.StockOfAsync(refs.StoreId, productId)).Should().Be(7m);
+
+        // Unpost → возвращаем на склад.
+        using var unpost = await api.Http.PostAsJsonAsync($"/api/inventory/losses/{lossId}/unpost", new { });
+        unpost.IsSuccessStatusCode.Should().BeTrue();
+        (await api.StockOfAsync(refs.StoreId, productId)).Should().Be(10m);
+    }
+
+    [Fact]
+    public async Task Cannot_write_off_more_than_available()
+    {
+        var api = new ApiActor(_factory.CreateClient());
+        await api.SignupAndLoginAsync($"loss-over-{Guid.NewGuid():N}");
+        var refs = await api.LoadRefsAsync();
+        var productId = await api.CreateProductAsync(refs, $"Prod-{Guid.NewGuid():N}", 200m, RandomBarcode());
+
+        // 2 шт на остатке.
+        var enter = await api.Http.PostAsJsonAsync("/api/inventory/enters", new
+        {
+            date = DateTime.UtcNow, storeId = refs.StoreId, currencyId = refs.CurrencyId,
+            notes = "seed-small", lines = new[] { new { productId, quantity = 2m, unitCost = 50m } },
+        });
+        enter.EnsureSuccessStatusCode();
+        var enterId = (await enter.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+        (await api.Http.PostAsJsonAsync($"/api/inventory/enters/{enterId}/post", new { })).EnsureSuccessStatusCode();
+
+        // Списать 5 шт — больше чем есть.
+        var loss = await api.Http.PostAsJsonAsync("/api/inventory/losses", new
+        {
+            date = DateTime.UtcNow, storeId = refs.StoreId, currencyId = refs.CurrencyId, reason = 0,
+            notes = "over", lines = new[] { new { productId, quantity = 5m, unitCost = 50m } },
+        });
+        loss.EnsureSuccessStatusCode();
+        var lossId = (await loss.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+
+        using var post = await api.Http.PostAsJsonAsync($"/api/inventory/losses/{lossId}/post", new { });
+        ((int)post.StatusCode).Should().Be(409);
+        // Остаток не должен измениться.
+        (await api.StockOfAsync(refs.StoreId, productId)).Should().Be(2m);
+    }
+
+    [Fact]
+    public async Task Tenant_isolation_loss()
+    {
+        var a = new ApiActor(_factory.CreateClient());
+        var b = new ApiActor(_factory.CreateClient());
+        await a.SignupAndLoginAsync($"loss-iso-a-{Guid.NewGuid():N}");
+        await b.SignupAndLoginAsync($"loss-iso-b-{Guid.NewGuid():N}");
+        var refsA = await a.LoadRefsAsync();
+        var productA = await a.CreateProductAsync(refsA, $"Prod-{Guid.NewGuid():N}", 100m, RandomBarcode());
+
+        var resp = await a.Http.PostAsJsonAsync("/api/inventory/losses", new
+        {
+            date = DateTime.UtcNow, storeId = refsA.StoreId, currencyId = refsA.CurrencyId, reason = 0,
+            notes = "iso", lines = new[] { new { productId = productA, quantity = 1m, unitCost = 10m } },
+        });
+        resp.EnsureSuccessStatusCode();
+        var lossId = (await resp.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id").GetString();
+
+        var bList = await b.ListAsync("/api/inventory/losses?pageSize=200");
+        bList.Should().NotContain(x => x.GetProperty("id").GetString() == lossId);
+
+        using var direct = await b.Http.GetAsync($"/api/inventory/losses/{lossId}");
+        direct.StatusCode.Should().Be(System.Net.HttpStatusCode.NotFound);
+    }
+}