fix: 全面修复6项问题——Auto模型路由/媒体提示词优化/微信Bot/Token驾驶舱/技能市场清空

1. resolve_auto_model: image/video/audio无显式默认时自动发现启用模型(原返回None→文本模型回退→AI说无法生成)
2. 新增_optimize_media_prompt: 调用文本LLM精炼用户原始输入为AGNES高质量提示词(去除对话噪音+英文优化)
3. detect_media_intent: 扩展关键词覆盖多轮对话模式(做图片/生成个图/画一下/制作视频等)
4. chat.py+im_llm.py: 所有httpx调用补trust_env=False+_proxy_for_url, 规避容器坏代理
5. token_usage.py: 模型名回退链(model表→日志自带的model_name→auto标签), 不再显示unknown
6. skills_admin.py: 新增POST /batch-delete批量删除API(ids空则删全部)
7. 技能市场数据已清空, 用户可重新导入技能

backend/python/app/api/token_usage.py

@@ -84,9 +84,20 @@ def get_rankings(
     models_list = []
     for r in model_rankings:
         model = db.query(AIModel).filter(AIModel.id == r.model_id).first()
+        if model:
+            model_name = model.name
+        else:
+            # 模型已被删除，从最近一条日志中取 model_name 作为回退
+            recent = db.query(TokenUsageLog.model_name).filter(
+                TokenUsageLog.model_id == r.model_id,
+                TokenUsageLog.model_name.isnot(None),
+            ).first()
+            model_name = (recent.model_name if recent else None) or (
+                "Auto 智能匹配" if r.model_id == "auto" else "未知模型"
+            )
         models_list.append({
             "model_id": r.model_id,
-            "model_name": model.name if model else "unknown",
+            "model_name": model_name,
             "total_tokens": int(r.total),
             "usage_count": int(r.count),
         })
@@ -162,10 +173,18 @@ def get_token_logs(
     result = []
     for log_item in logs:
         model = db.query(AIModel).filter(AIModel.id == log_item.model_id).first()
+        if model:
+            model_name = model.name
+        elif log_item.model_name:
+            model_name = log_item.model_name  # 日志自带的名称
+        elif log_item.model_id == "auto":
+            model_name = "🤖 Auto 智能匹配"
+        else:
+            model_name = "未知模型 (ID: {})".format(log_item.model_id[:8] if log_item.model_id else "?")
         result.append({
             "id": log_item.id,
             "model_id": log_item.model_id,
-            "model_name": model.name if model else "unknown",
+            "model_name": model_name,
             "prompt_tokens": log_item.prompt_tokens or 0,
             "completion_tokens": log_item.completion_tokens or 0,
             "total_tokens": log_item.total_tokens or 0,