Stage 4 — Labor Catalog: fixed price + default parts + service templates

Schema:
- labors.pricing_mode (hourly/fixed) + fixed_price
- labor_parts (default parts auto-added with a labor)
- service_templates + service_template_items (labor/part bundles)

ServiceComposer:
- addLabor(wo, labor, withParts) — hourly (hours×rate) or fixed (fixed_price),
  then auto-adds the labor's default parts
- addPart(wo, part, qty) — catalog price snapshot
- applyTemplate(wo, template) — adds all labor+part lines, recalcs total
- hourlyRate from settings.labor_rate

Filament:
- LaborResource: pricing_mode (live) toggles hours/fixed_price fields,
  DefaultPartsRelationManager
- ServiceTemplateResource (Service group) with ItemsRelationManager
- WorkOrder edit "Aplică șablon" action → applyTemplate
- WorksRelationManager CreateAction auto-adds labor default parts

Tests (6 new):
- hourly rate×hours; fixed uses fixed_price; default parts auto-added;
  withParts=false skips; applyTemplate adds lines + recalcs total;
  templates tenant-isolated

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

app/Models/Tenant/LaborPart.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Models\Tenant;
+
+use App\Models\Concerns\BelongsToTenant;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class LaborPart extends Model
+{
+    use BelongsToTenant;
+
+    protected $fillable = ['company_id', 'labor_id', 'part_id', 'qty', 'unit'];
+
+    protected $casts = ['qty' => 'decimal:2'];
+
+    public function labor(): BelongsTo
+    {
+        return $this->belongsTo(Labor::class);
+    }
+
+    public function part(): BelongsTo
+    {
+        return $this->belongsTo(Part::class);
+    }
+}