feat(allocation): implement resource allocation feature

- Add AllocationController with CRUD + bulk endpoints
- Add AllocationValidationService for capacity/estimate validation
- Add AllocationMatrixService for optimized matrix queries
- Add AllocationPolicy for authorization
- Add AllocationResource for API responses
- Add frontend allocationService and matrix UI
- Add E2E tests for allocation matrix (20 tests)
- Add unit tests for validation service and policies
- Fix month format conversion (YYYY-MM to YYYY-MM-01)

backend/app/Http/Resources/AllocationResource.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Http\Resources;
+
+use Illuminate\Http\Request;
+
+class AllocationResource extends BaseResource
+{
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->id,
+            'project_id' => $this->project_id,
+            'team_member_id' => $this->team_member_id,
+            'month' => $this->month?->format('Y-m'),
+            'allocated_hours' => $this->formatDecimal($this->allocated_hours),
+            'created_at' => $this->formatDate($this->created_at),
+            'updated_at' => $this->formatDate($this->updated_at),
+            'project' => $this->whenLoaded('project', fn () => new ProjectResource($this->project)),
+            'team_member' => $this->whenLoaded('teamMember', fn () => new TeamMemberResource($this->teamMember)),
+        ];
+    }
+}