Handle fractional session timestamps on Python 3.10

app.py

@@ -521,7 +521,18 @@ def results(session_id: UUID, request: Request):
             "postActionMetrics": [], "fullIntervalMetrics": full_interval_metrics,
             "skeleton": report.get("skeleton_history", []), "rawAnalytics": analytics})
     created = row.get("created_at")
-    created_at = datetime.fromisoformat(created.replace("Z", "+00:00")) if created else datetime.now(timezone.utc)
+    if created:
+        created_iso = created.replace("Z", "+00:00")
+        # Python 3.10's fromisoformat requires a six-digit fractional second,
+        # while the API may return a shorter fraction such as `.89`.
+        created_iso = re.sub(
+            r"(?<=\.)\d+(?=(?:[+-]\d{2}:\d{2})?$)",
+            lambda match: match.group(0)[:6].ljust(6, "0"),
+            created_iso,
+        )
+        created_at = datetime.fromisoformat(created_iso)
+    else:
+        created_at = datetime.now(timezone.utc)
     if created_at.tzinfo is None:
         created_at = created_at.replace(tzinfo=timezone.utc)
     return {"id": str(session_id), "playerId": row["player_id"], "playerName": "",