Refactor app structure and simplify team docs

backend/app/routes/__init__.py

@@ -0,0 +1,13 @@
+from .auth import register_auth_routes
+from .integration import register_integration_routes
+from .organization import register_member_routes
+from .seatmap import register_seatmap_routes
+from .system import register_system_routes
+
+__all__ = [
+    "register_auth_routes",
+    "register_integration_routes",
+    "register_member_routes",
+    "register_seatmap_routes",
+    "register_system_routes",
+]