Move auth server from federation to account

Account is now the OAuth authorization server with magic link login,
OAuth2 authorize endpoint, SSO logout, and session management.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

market/models/__init__.py

@@ -0,0 +1,8 @@
+from .market import (
+    Product, ProductLike, ProductImage, ProductSection,
+    NavTop, NavSub, Listing, ListingItem,
+    LinkError, LinkExternal, SubcategoryRedirect, ProductLog,
+    ProductLabel, ProductSticker, ProductAttribute, ProductNutrition, ProductAllergen,
+    CartItem,
+)
+from .market_place import MarketPlace

market/models/market.py

@@ -0,0 +1,7 @@
+from shared.models.market import (  # noqa: F401
+    Product, ProductLike, ProductImage, ProductSection,
+    NavTop, NavSub, Listing, ListingItem,
+    LinkError, LinkExternal, SubcategoryRedirect, ProductLog,
+    ProductLabel, ProductSticker, ProductAttribute, ProductNutrition, ProductAllergen,
+    CartItem,
+)

market/models/market_place.py

@@ -0,0 +1 @@
+from shared.models.market_place import MarketPlace  # noqa: F401