feat: complete modular platform architecture (Phases 1-5)

Phase 1 - Vendor Router Integration:
- Wire up vendor module routers in app/api/v1/vendor/__init__.py
- Use lazy imports via __getattr__ to avoid circular dependencies

Phase 2 - Extract Remaining Modules:
- Create 6 new module directories: customers, cms, analytics, messaging,
  dev_tools, monitoring
- Each module has definition.py and route wrappers
- Update registry to import from extracted modules

Phase 3 - Database Table Migration:
- Add PlatformModule junction table for auditable module tracking
- Add migration zc2m3n4o5p6q7_add_platform_modules_table.py
- Add modules relationship to Platform model
- Update ModuleService with JSON-to-junction-table migration

Phase 4 - Module-Specific Configuration UI:
- Add /api/v1/admin/module-config/* endpoints
- Add module-config.html template and JS

Phase 5 - Integration Tests:
- Add tests/fixtures/module_fixtures.py
- Add tests/integration/api/v1/admin/test_modules.py
- Add tests/integration/api/v1/modules/test_module_access.py

Architecture fixes:
- Fix JS-003 errors: use ...data() directly in Alpine components
- Fix JS-005 warnings: add init() guards to prevent duplicate init
- Fix API-001 errors: add MenuActionResponse Pydantic model
- Add FE-008 noqa for dynamic number input in template

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/orders/routes/admin.py

@@ -15,9 +15,9 @@ from fastapi import APIRouter, Depends
 
 from app.api.deps import require_module_access
 
-# Import original routers
-from app.api.v1.admin import orders as orders_routes
-from app.api.v1.admin import order_item_exceptions as exceptions_routes
+# Import original routers (direct import to avoid circular dependency)
+from app.api.v1.admin.orders import router as orders_original_router
+from app.api.v1.admin.order_item_exceptions import router as exceptions_original_router
 
 # Create module-aware router for orders
 admin_router = APIRouter(
@@ -26,7 +26,7 @@ admin_router = APIRouter(
 )
 
 # Re-export all routes from the original orders module
-for route in orders_routes.router.routes:
+for route in orders_original_router.routes:
     admin_router.routes.append(route)
 
 # Create separate router for order item exceptions
@@ -36,5 +36,5 @@ admin_exceptions_router = APIRouter(
     dependencies=[Depends(require_module_access("orders"))],
 )
 
-for route in exceptions_routes.router.routes:
+for route in exceptions_original_router.routes:
     admin_exceptions_router.routes.append(route)