feat(backend): enhance allocation and project management

Update controllers and services for allocation fidelity:
- AllocationController: variance data in responses, bulk operations
- ProjectController: include plan data in responses
- ProjectMonthPlanController: planning grid API
- AllocationMatrixService: support untracked allocations
- ProjectResource/TeamMemberResource: include reconciliation data

Improved test coverage for allocation flows.

backend/tests/Unit/Resources/TeamMemberResourceTest.php

@@ -21,6 +21,18 @@ test('team member resource wraps data and includes role when loaded', function (
     expect($payload['data']['role']['id'])->toBe($role->id);
 });
 
+test('team member resource includes scalar role_id', function () {
+    $role = Role::factory()->create();
+    $teamMember = TeamMember::factory()->create(['role_id' => $role->id]);
+    $teamMember->load('role');
+
+    $response = (new TeamMemberResource($teamMember))->toResponse(Request::create('/'));
+    $payload = $response->getData(true);
+
+    expect($payload['data'])->toHaveKey('role_id');
+    expect($payload['data']['role_id'])->toBe($teamMember->role_id);
+});
+
 test('team member resource collection keeps data wrapper', function () {
     $role = Role::factory()->create();
     $teamMembers = TeamMember::factory()->count(2)->create(['role_id' => $role->id]);