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/app/Http/Resources/TeamMemberResource.php

@@ -12,6 +12,7 @@ class TeamMemberResource extends BaseResource
         return [
             'id' => $this->id,
             'name' => $this->name,
+            'role_id' => $this->role_id,
             'role' => $this->whenLoaded('role', fn () => new RoleResource($this->role)),
             'hourly_rate' => $this->formatDecimal($this->hourly_rate),
             'active' => $this->active,