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/messaging/routes/__init__.py

@@ -0,0 +1,34 @@
+# app/modules/messaging/routes/__init__.py
+"""
+Messaging module route registration.
+
+This module provides functions to register messaging routes
+with module-based access control.
+
+NOTE: Routers are NOT auto-imported to avoid circular dependencies.
+Import directly from admin.py or vendor.py as needed:
+  from app.modules.messaging.routes.admin import admin_router, admin_notifications_router
+  from app.modules.messaging.routes.vendor import vendor_router, vendor_notifications_router
+"""
+
+# Routers are imported on-demand to avoid circular dependencies
+# Do NOT add auto-imports here
+
+__all__ = ["admin_router", "admin_notifications_router", "vendor_router", "vendor_notifications_router"]
+
+
+def __getattr__(name: str):
+    """Lazy import routers to avoid circular dependencies."""
+    if name == "admin_router":
+        from app.modules.messaging.routes.admin import admin_router
+        return admin_router
+    elif name == "admin_notifications_router":
+        from app.modules.messaging.routes.admin import admin_notifications_router
+        return admin_notifications_router
+    elif name == "vendor_router":
+        from app.modules.messaging.routes.vendor import vendor_router
+        return vendor_router
+    elif name == "vendor_notifications_router":
+        from app.modules.messaging.routes.vendor import vendor_notifications_router
+        return vendor_notifications_router
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

app/modules/messaging/routes/admin.py

@@ -0,0 +1,39 @@
+# app/modules/messaging/routes/admin.py
+"""
+Messaging module admin routes.
+
+This module wraps the existing admin messages and notifications routes
+and adds module-based access control. Routes are re-exported from the
+original location with the module access dependency.
+
+Includes:
+- /messages/* - Message management
+- /notifications/* - Notification management
+"""
+
+from fastapi import APIRouter, Depends
+
+from app.api.deps import require_module_access
+
+# Import original routers (direct import to avoid circular dependency)
+from app.api.v1.admin.messages import router as messages_original_router
+from app.api.v1.admin.notifications import router as notifications_original_router
+
+# Create module-aware router for messages
+admin_router = APIRouter(
+    prefix="/messages",
+    dependencies=[Depends(require_module_access("messaging"))],
+)
+
+# Re-export all routes from the original messages module
+for route in messages_original_router.routes:
+    admin_router.routes.append(route)
+
+# Create separate router for notifications
+admin_notifications_router = APIRouter(
+    prefix="/notifications",
+    dependencies=[Depends(require_module_access("messaging"))],
+)
+
+for route in notifications_original_router.routes:
+    admin_notifications_router.routes.append(route)

app/modules/messaging/routes/vendor.py

@@ -0,0 +1,39 @@
+# app/modules/messaging/routes/vendor.py
+"""
+Messaging module vendor routes.
+
+This module wraps the existing vendor messages and notifications routes
+and adds module-based access control. Routes are re-exported from the
+original location with the module access dependency.
+
+Includes:
+- /messages/* - Message management
+- /notifications/* - Notification management
+"""
+
+from fastapi import APIRouter, Depends
+
+from app.api.deps import require_module_access
+
+# Import original routers (direct import to avoid circular dependency)
+from app.api.v1.vendor.messages import router as messages_original_router
+from app.api.v1.vendor.notifications import router as notifications_original_router
+
+# Create module-aware router for messages
+vendor_router = APIRouter(
+    prefix="/messages",
+    dependencies=[Depends(require_module_access("messaging"))],
+)
+
+# Re-export all routes from the original messages module
+for route in messages_original_router.routes:
+    vendor_router.routes.append(route)
+
+# Create separate router for notifications
+vendor_notifications_router = APIRouter(
+    prefix="/notifications",
+    dependencies=[Depends(require_module_access("messaging"))],
+)
+
+for route in notifications_original_router.routes:
+    vendor_notifications_router.routes.append(route)