feat: complete marketplace module self-containment

Migrate marketplace module to self-contained structure:

- routes/api/admin.py - Admin API endpoints
- routes/api/vendor.py - Vendor API endpoints
- routes/pages/ - Page routes (placeholder)
- models/letzshop.py - Letzshop model
- models/marketplace_import_job.py - Import job model
- models/marketplace_product.py - Product model
- models/marketplace_product_translation.py - Translation model
- schemas/marketplace_import_job.py - Import job schemas
- schemas/marketplace_product.py - Product schemas
- locales/ - Translations (en, de, fr, lu)

Removed legacy route files replaced by api/ structure.
Updated __init__.py files to use new structure.

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

app/modules/marketplace/routes/api/admin.py

@@ -0,0 +1,44 @@
+# app/modules/marketplace/routes/api/admin.py
+"""
+Marketplace module admin routes.
+
+This module wraps the existing admin marketplace routes and adds
+module-based access control. Routes are re-exported from the
+original location with the module access dependency.
+
+Includes:
+- /marketplace/* - Marketplace monitoring
+- /letzshop/* - Letzshop integration
+"""
+
+import importlib
+
+from fastapi import APIRouter, Depends
+
+from app.api.deps import require_module_access
+
+# Import original routers using importlib to avoid circular imports
+# (direct import triggers app.api.v1.admin.__init__.py which imports us)
+_marketplace_module = importlib.import_module("app.api.v1.admin.marketplace")
+_letzshop_module = importlib.import_module("app.api.v1.admin.letzshop")
+marketplace_original_router = _marketplace_module.router
+letzshop_original_router = _letzshop_module.router
+
+# Create module-aware router for marketplace
+admin_router = APIRouter(
+    prefix="/marketplace",
+    dependencies=[Depends(require_module_access("marketplace"))],
+)
+
+# Re-export all routes from the original marketplace module
+for route in marketplace_original_router.routes:
+    admin_router.routes.append(route)
+
+# Create separate router for letzshop integration
+admin_letzshop_router = APIRouter(
+    prefix="/letzshop",
+    dependencies=[Depends(require_module_access("marketplace"))],
+)
+
+for route in letzshop_original_router.routes:
+    admin_letzshop_router.routes.append(route)