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/customers/__init__.py

@@ -0,0 +1,22 @@
+# app/modules/customers/__init__.py
+"""
+Customers Module - Customer database and management.
+
+This module provides:
+- Customer profiles and contact information
+- Customer segmentation and tags
+- Purchase history tracking
+- Customer exports
+
+Routes:
+- Admin: /api/v1/admin/customers/*
+- Vendor: /api/v1/vendor/customers/*
+
+Menu Items:
+- Admin: customers
+- Vendor: customers
+"""
+
+from app.modules.customers.definition import customers_module
+
+__all__ = ["customers_module"]

app/modules/customers/definition.py

@@ -0,0 +1,62 @@
+# app/modules/customers/definition.py
+"""
+Customers module definition.
+
+Defines the customers 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.customers.routes.admin import admin_router
+
+    return admin_router
+
+
+def _get_vendor_router():
+    """Lazy import of vendor router to avoid circular imports."""
+    from app.modules.customers.routes.vendor import vendor_router
+
+    return vendor_router
+
+
+# Customers module definition
+customers_module = ModuleDefinition(
+    code="customers",
+    name="Customer Management",
+    description="Customer database, profiles, and segmentation.",
+    features=[
+        "customer_view",  # View customer profiles
+        "customer_export",  # Export customer data
+        "customer_profiles",  # Detailed customer profiles
+        "customer_segmentation",  # Customer tagging and segments
+    ],
+    menu_items={
+        FrontendType.ADMIN: [
+            "customers",  # Platform-wide customer view
+        ],
+        FrontendType.VENDOR: [
+            "customers",  # Vendor customer list
+        ],
+    },
+    is_core=False,
+)
+
+
+def get_customers_module_with_routers() -> ModuleDefinition:
+    """
+    Get customers module with routers attached.
+
+    This function attaches the routers lazily to avoid circular imports
+    during module initialization.
+    """
+    customers_module.admin_router = _get_admin_router()
+    customers_module.vendor_router = _get_vendor_router()
+    return customers_module
+
+
+__all__ = ["customers_module", "get_customers_module_with_routers"]

app/modules/customers/routes/__init__.py

@@ -0,0 +1,28 @@
+# app/modules/customers/routes/__init__.py
+"""
+Customers module route registration.
+
+This module provides functions to register customers 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.customers.routes.admin import admin_router
+  from app.modules.customers.routes.vendor import vendor_router
+"""
+
+# Routers are imported on-demand to avoid circular dependencies
+# Do NOT add auto-imports here
+
+__all__ = ["admin_router", "vendor_router"]
+
+
+def __getattr__(name: str):
+    """Lazy import routers to avoid circular dependencies."""
+    if name == "admin_router":
+        from app.modules.customers.routes.admin import admin_router
+        return admin_router
+    elif name == "vendor_router":
+        from app.modules.customers.routes.vendor import vendor_router
+        return vendor_router
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

app/modules/customers/routes/admin.py

@@ -0,0 +1,25 @@
+# app/modules/customers/routes/admin.py
+"""
+Customers module admin routes.
+
+This module wraps the existing admin customers routes and adds
+module-based access control. Routes are re-exported from the
+original location with the module access dependency.
+"""
+
+from fastapi import APIRouter, Depends
+
+from app.api.deps import require_module_access
+
+# Import original router (direct import to avoid circular dependency)
+from app.api.v1.admin.customers import router as original_router
+
+# Create module-aware router
+admin_router = APIRouter(
+    prefix="/customers",
+    dependencies=[Depends(require_module_access("customers"))],
+)
+
+# Re-export all routes from the original module with module access control
+for route in original_router.routes:
+    admin_router.routes.append(route)

app/modules/customers/routes/vendor.py

@@ -0,0 +1,25 @@
+# app/modules/customers/routes/vendor.py
+"""
+Customers module vendor routes.
+
+This module wraps the existing vendor customers routes and adds
+module-based access control. Routes are re-exported from the
+original location with the module access dependency.
+"""
+
+from fastapi import APIRouter, Depends
+
+from app.api.deps import require_module_access
+
+# Import original router (direct import to avoid circular dependency)
+from app.api.v1.vendor.customers import router as original_router
+
+# Create module-aware router
+vendor_router = APIRouter(
+    prefix="/customers",
+    dependencies=[Depends(require_module_access("customers"))],
+)
+
+# Re-export all routes from the original module with module access control
+for route in original_router.routes:
+    vendor_router.routes.append(route)