feat(15-05): getWidgets filters via ModuleAccessService (D-22, PERM-07)

- DashboardModule imports ModuleRegistryModule to inject ModuleAccessService
- getWidgets(userId, tenantId, role) runs the existing findMany unchanged
  first, then calls getAccessibleModuleIds exactly once — only if a loaded
  widget's type is in WIDGET_MODULE_MAP (currently always empty, so no
  lookup runs today); unresolved module slugs fail closed
- DashboardController.getWidgets forwards tenantId + role from the JWT
- dashboard.service.spec.ts (8 tests, TDD-GREEN): covers every <behavior>
  case incl. D-03 ADMIN bypass, adjacency/empty/ordering/idempotency, and
  fail-closed on an unresolved Module slug
- pnpm --filter @tessera/api test: 457/457 green; type-check clean
- manual e2e against local API + DB container: empty WIDGET_MODULE_MAP
  leaves an existing user's widget count unchanged (2/2 clock+search
  survived the filter), throwaway verification user/rows removed after

apps/api/src/dashboard/dashboard.controller.ts

@@ -68,8 +68,9 @@ export class DashboardController {
 
   @Get('widgets')
   async getWidgets(@Req() req: Request) {
-    const { userId } = this.extractContext(req);
-    return this.dashboardService.getWidgets(userId);
+    const { userId, tenantId } = this.extractContext(req);
+    const role = (req as any).user?.role;
+    return this.dashboardService.getWidgets(userId, tenantId, role);
   }
 
   @Post('widgets')