fix: convert Decimal to float in API responses instead of string — fixes positions page crash

services/api/app.py

@@ -82,10 +82,17 @@ app.add_middleware(TraceMiddleware)
 
 def _row_to_dict(row: asyncpg.Record) -> dict[str, Any]:
     """Convert an asyncpg Record to a JSON-safe dict."""
+    from decimal import Decimal
+    from uuid import UUID
+
     d: dict[str, Any] = {}
     for key, val in dict(row).items():
         if isinstance(val, datetime):
             d[key] = val.isoformat()
+        elif isinstance(val, Decimal):
+            d[key] = float(val)
+        elif isinstance(val, UUID):
+            d[key] = str(val)
         elif hasattr(val, "__str__") and not isinstance(val, (str, int, float, bool, list, dict, type(None))):
             d[key] = str(val)
         else: