fix: Add error handling to analytics API functions

- Add try/except to get_analytics_stats_json()
- Add try/except to get_conversation_history_json()
- Prevents uncaught exceptions from crashing API endpoints

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -1260,14 +1260,22 @@ def get_analytics_stats_json() -> Dict[str, Any]:
     """Get analytics stats as JSON for API"""
     if not ANALYTICS_AVAILABLE or analytics is None:
         return {"error": "Analytics not available"}
-    return analytics.get_stats()
+    try:
+        return analytics.get_stats()
+    except Exception as e:
+        logger.error(f"[ANALYTICS_ERROR] get_stats failed: {e}")
+        return {"error": str(e)}
 
 
 def get_conversation_history_json(limit: int = 50) -> List[Dict[str, Any]]:
     """Get conversation history as JSON for API"""
     if not ANALYTICS_AVAILABLE or analytics is None:
         return [{"error": "Analytics not available"}]
-    return analytics.get_conversation_history(limit)
+    try:
+        return analytics.get_conversation_history(limit)
+    except Exception as e:
+        logger.error(f"[ANALYTICS_ERROR] get_conversation_history failed: {e}")
+        return [{"error": str(e)}]
 
 
 # ========== Session Archive Functions ==========