fix: evaluate_turn_regex crashes on a non-string agent_reply (#1723)

src/teacher_escalation.py

@@ -112,7 +112,7 @@ def evaluate_turn_regex(
                     return ("failure", f"tool result matched error pattern {pat.pattern!r}: {snippet!r}")
 
     # Agent verbally gave up?
-    if agent_reply:
+    if isinstance(agent_reply, str) and agent_reply:
         for pat in _REPLY_GIVE_UP_PATTERNS:
             m = pat.search(agent_reply)
             if m: