fix: correct module definitions for cart, catalog, checkout

- Fix cart to import from app.modules.base instead of non-existent
  app.modules.core.module_registry
- Change 'dependencies' to 'requires' (correct attribute name)
- Remove invalid 'provides_*' attributes that don't exist in
  ModuleDefinition dataclass

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

app/modules/catalog/definition.py

@@ -9,9 +9,5 @@ module = ModuleDefinition(
     description="Product catalog browsing and search for storefronts",
     version="1.0.0",
     is_self_contained=True,
-    dependencies=["inventory"],
-    provides_models=False,  # Uses Product model from products module
-    provides_schemas=True,
-    provides_services=True,
-    provides_api_routes=True,
+    requires=["inventory"],
 )