refactor: use _should_sanitize_tool_calls in flush_memories()

Replaces hardcoded Mistral check with the new _should_sanitize_tool_calls()
method. This ensures tool_calls are sanitized for all strict APIs, not
just Mistral. Prevents 400 errors from Fireworks and other providers.

run_agent.py

@@ -5396,7 +5396,7 @@ class AIAgent:
 
         try:
             # Build API messages for the flush call
-            _is_strict_api = "api.mistral.ai" in self._base_url_lower
+            _needs_sanitize = self._should_sanitize_tool_calls()
             api_messages = []
             for msg in messages:
                 api_msg = msg.copy()
@@ -5407,7 +5407,7 @@ class AIAgent:
                 api_msg.pop("reasoning", None)
                 api_msg.pop("finish_reason", None)
                 api_msg.pop("_flush_sentinel", None)
-                if _is_strict_api:
+                if _needs_sanitize:
                     self._sanitize_tool_calls_for_strict_api(api_msg)
                 api_messages.append(api_msg)