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/monitoring/definition.py

@@ -0,0 +1,59 @@
+# app/modules/monitoring/definition.py
+"""
+Monitoring module definition.
+
+Defines the monitoring module including its features, menu items,
+and route configurations.
+"""
+
+from app.modules.base import ModuleDefinition
+from models.database.admin_menu_config import FrontendType
+
+
+def _get_admin_router():
+    """Lazy import of admin router to avoid circular imports."""
+    from app.modules.monitoring.routes.admin import admin_router
+
+    return admin_router
+
+
+# Monitoring module definition
+monitoring_module = ModuleDefinition(
+    code="monitoring",
+    name="Platform Monitoring",
+    description="Logs, background tasks, imports, and system health.",
+    features=[
+        "application_logs",  # Log viewing
+        "background_tasks",  # Task monitoring
+        "import_jobs",  # Import job tracking
+        "capacity_monitoring",  # System capacity
+        "testing_hub",  # Test runner
+        "code_quality",  # Code quality tools
+    ],
+    menu_items={
+        FrontendType.ADMIN: [
+            "imports",  # Import jobs
+            "background-tasks",  # Background tasks
+            "logs",  # Application logs
+            "platform-health",  # Platform health
+            "testing",  # Testing hub
+            "code-quality",  # Code quality
+        ],
+        FrontendType.VENDOR: [],  # No vendor menu items
+    },
+    is_core=False,
+)
+
+
+def get_monitoring_module_with_routers() -> ModuleDefinition:
+    """
+    Get monitoring module with routers attached.
+
+    This function attaches the routers lazily to avoid circular imports
+    during module initialization.
+    """
+    monitoring_module.admin_router = _get_admin_router()
+    return monitoring_module
+
+
+__all__ = ["monitoring_module", "get_monitoring_module_with_routers"]