feat(ui): implement premium beige design system and ux refinements

backend/app/analytics/event_recorder.py

@@ -4,6 +4,8 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING, Any, Protocol, runtime_checkable
 
+from psycopg.types.json import Json
+
 if TYPE_CHECKING:
     from psycopg_pool import AsyncConnectionPool
 
@@ -89,7 +91,7 @@ class PostgresAnalyticsRecorder:
             "duration_ms": duration_ms,
             "success": success,
             "error_message": error_message,
-            "metadata": metadata or {},
+            "metadata": Json(metadata or {}),
         }
         async with self._pool.connection() as conn:
             await conn.execute(_INSERT_SQL, params)