Stage 5.1 — Warehouse ERP: batches + FIFO + reservations + multi-warehouse

Schema:
- warehouses (multi-warehouse, code unique per company, is_default)
- part_batches (lot per receipt, qty_in/qty_remaining, buy_price, FIFO-indexed)
- warehouse_events (immutable ledger: opening/receipt/issue/transfer/adjustment/write_off)
- part_reservations (per-WO allocations from specific batches, active/consumed/released)
- companies.default_warehouse_id + parts.qty_reserved

Backfill: 1 default warehouse + 1 opening batch per existing part per company.

WarehouseService:
- receive / issue (FIFO) / reserve / release / consume / transfer / adjust
- DB::transaction + lockForUpdate on batch rows
- InsufficientStockException with requested + available context
- Auto-syncs parts.qty as aggregate cache (source of truth = sum(qty_remaining))

WO integration:
- WorkOrderPart created/updated → reserve from FIFO batches
- WorkOrderPart deleted → release
- WorkOrder status=done → consume reservations into issue events
- WorkOrder status=cancelled → release reservations

Filament:
- WarehouseResource (CRUD)
- BatchesRelationManager on PartResource (FIFO list with qty_remaining + cost)
- "Recepție" action on parts list → calls WarehouseService::receive
- qty_reserved column added on parts list

Tests (8 new, all pass):
- receipt creates batch + event
- FIFO order verified across 3 batches with different received_at
- InsufficientStockException on over-issue
- Reservations block other reservations but don't deplete on-hand
- WO done consumes; WO cancelled releases
- Batches tenant-isolated
- Transfer between warehouses with weighted-avg cost

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Filament/Tenant/Resources/PartResource.php

@@ -3,6 +3,7 @@
 namespace App\Filament\Tenant\Resources;
 
 use App\Filament\Tenant\Resources\PartResource\Pages;
+use App\Filament\Tenant\Resources\PartResource\RelationManagers;
 use App\Models\Tenant\Part;
 use App\Models\Tenant\Supplier;
 use Filament\Actions;
@@ -112,6 +113,12 @@ class PartResource extends Resource
                     ->alignRight()
                     ->color(fn ($state, $record) => $record->qty <= 0 ? 'danger' : ($record->qty <= $record->min_qty ? 'warning' : null))
                     ->weight(fn ($state, $record) => $record->qty <= $record->min_qty ? 'bold' : null),
+                Tables\Columns\TextColumn::make('qty_reserved')
+                    ->label('Rezervat')
+                    ->numeric(decimalPlaces: 2)
+                    ->alignRight()
+                    ->color(fn ($state) => (float) $state > 0 ? 'info' : null)
+                    ->toggleable(),
                 Tables\Columns\TextColumn::make('unit')->label('UM'),
                 Tables\Columns\TextColumn::make('location')->label('Loc.')->placeholder('—'),
                 Tables\Columns\TextColumn::make('sell_price')->label('Preț vz.')->money('MDL')->alignRight(),
@@ -128,6 +135,42 @@ class PartResource extends Resource
                     ->query(fn ($q) => $q->where('qty', '<=', 0)),
             ])
             ->actions([
+                Actions\Action::make('receive')
+                    ->label('Recepție')
+                    ->icon('heroicon-m-arrow-down-tray')
+                    ->color('success')
+                    ->schema([
+                        Forms\Components\TextInput::make('qty')->label('Cantitate')->numeric()->required()->minValue(0.001),
+                        Forms\Components\TextInput::make('buy_price')->label('Preț unitar')->numeric()->required(),
+                        Forms\Components\Select::make('supplier_id')
+                            ->label('Furnizor')
+                            ->options(fn () => \App\Models\Tenant\Supplier::pluck('name', 'id')),
+                        Forms\Components\Select::make('warehouse_id')
+                            ->label('Depozit')
+                            ->options(fn () => \App\Models\Tenant\Warehouse::where('is_active', true)->pluck('name', 'id'))
+                            ->default(fn () => \App\Models\Tenant\Warehouse::where('is_default', true)->value('id')),
+                        Forms\Components\TextInput::make('batch_ref')->label('Ref. lot/factură')->maxLength(64),
+                    ])
+                    ->action(function (Part $record, array $data) {
+                        $warehouse = $data['warehouse_id']
+                            ? \App\Models\Tenant\Warehouse::find($data['warehouse_id'])
+                            : null;
+                        $supplier = $data['supplier_id']
+                            ? \App\Models\Tenant\Supplier::find($data['supplier_id'])
+                            : null;
+                        app(\App\Services\Warehouse\WarehouseService::class)->receive(
+                            part: $record,
+                            qty: (float) $data['qty'],
+                            buyPrice: (float) $data['buy_price'],
+                            warehouse: $warehouse,
+                            supplier: $supplier,
+                            batchRef: $data['batch_ref'] ?? null,
+                        );
+                        \Filament\Notifications\Notification::make()
+                            ->title('Stoc adăugat')
+                            ->success()
+                            ->send();
+                    }),
                 Actions\EditAction::make(),
                 Actions\DeleteAction::make(),
             ])
@@ -137,6 +180,13 @@ class PartResource extends Resource
             ->defaultSort('name');
     }
 
+    public static function getRelations(): array
+    {
+        return [
+            RelationManagers\BatchesRelationManager::class,
+        ];
+    }
+
     public static function getPages(): array
     {
         return [