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/Controllers/Api/CapacityController.php

@@ -195,4 +195,47 @@ class CapacityController extends Controller
 
         return $this->wrapResource(new TeamMemberAvailabilityResource($entry), 201);
     }
+
+    /**
+     * Batch Update Team Member Availability
+     *
+     * Persist multiple daily availability overrides in a single batch operation.
+     *
+     * @group Capacity Planning
+     *
+     * @bodyParam month string required The month in YYYY-MM format. Example: 2026-02
+     * @bodyParam updates array required Array of availability updates.
+     * @bodyParam updates[].team_member_id string required The team member UUID.
+     * @bodyParam updates[].date string required The date (YYYY-MM-DD).
+     * @bodyParam updates[].availability numeric required The availability value (0, 0.5, 1).
+     *
+     * @response {
+     *   "data": {
+     *     "saved": 12,
+     *     "month": "2026-02"
+     *   }
+     * }
+     */
+    public function batchUpdateAvailability(Request $request): JsonResponse
+    {
+        $data = $request->validate([
+            'month' => 'required|date_format:Y-m',
+            'updates' => 'present|array',
+            'updates.*.team_member_id' => 'required_with:updates|exists:team_members,id',
+            'updates.*.date' => 'required_with:updates|date_format:Y-m-d',
+            'updates.*.availability' => ['required_with:updates', 'numeric', Rule::in([0, 0.5, 1])],
+        ]);
+
+        $saved = $this->capacityService->batchUpsertAvailability(
+            $data['updates'],
+            $data['month']
+        );
+
+        return response()->json([
+            'data' => [
+                'saved' => $saved,
+                'month' => $data['month'],
+            ],
+        ]);
+    }
 }