feat: LLM 调用日志 + ModelSelector 优化 + devtools.bat 编码修复

- 新增 call_log.go: 全局环形缓冲区记录每次 LLM 调用(模型/Token/耗时/错误)
- OpenAIProvider.doChat/ChatStreamWithTools 自动记录调用日志
- ai-core 暴露 GET /api/v1/llm-calls 端点, DevTools 代理 + UI 面板
- ModelSelector.envProvider 改为单例缓存, 避免重复创建 HTTP Client
- 新增 PurposeToolCalling 适配器, 后台思考工具调用走专用路由
- envFallback 超时 120s→180s, 显式设置 MaxRetries
- devtools.bat 全英文, 解决 Windows CMD GBK 编码乱码问题

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/ai-core/cmd/main.go

@@ -67,7 +67,8 @@ func main() {
 		APIKey:        cfg.LLMAPIKey,
 		Model:         cfg.LLMModel,
 		FallbackModel: cfg.LLMFallbackModel,
-		Timeout:       120 * time.Second,
+		MaxRetries:    3,
+		Timeout:       180 * time.Second,
 	}
 
 	// 创建 ModelSelector (优先使用 models.json，回退到 .env)
@@ -82,10 +83,12 @@ func main() {
 	thinkerAdapter := llm.NewAdapter(provider)
 	provider, _ = modelSelector.Select(context.Background(), llm.PurposeMemoryExtraction)
 	memoryAdapter := llm.NewAdapter(provider)
+	provider, _ = modelSelector.Select(context.Background(), llm.PurposeToolCalling)
+	toolAdapter := llm.NewAdapter(provider)
 
 	if configLoader != nil && configLoader.HasConfig() {
-		log.Printf("LLM适配器已就绪: models.json 驱动 (chat=%s, intent=%s, think=%s, memory=%s)",
-			chatAdapter.ModelName(), intentAdapter.ModelName(), thinkerAdapter.ModelName(), memoryAdapter.ModelName())
+		log.Printf("LLM适配器已就绪: models.json 驱动 (chat=%s, intent=%s, think=%s, memory=%s, tool=%s)",
+			chatAdapter.ModelName(), intentAdapter.ModelName(), thinkerAdapter.ModelName(), memoryAdapter.ModelName(), toolAdapter.ModelName())
 	} else {
 		log.Printf("LLM适配器已就绪: .env 驱动 (模型=%s)", chatAdapter.ModelName())
 	}
@@ -193,6 +196,7 @@ func main() {
 		personaLoader,
 		memRetriever,
 		thinkerAdapter,
+		toolAdapter,
 		iotClient,
 		memStore,
 		toolRegistry,
@@ -311,6 +315,22 @@ func main() {
 		w.Write([]byte(`{"status":"ok","service":"ai-core","model":"` + chatAdapter.ModelName() + `"}`))
 	})
 
+	// LLM 调用日志（调试用）
+	mux.HandleFunc("/api/v1/llm-calls", func(w http.ResponseWriter, r *http.Request) {
+		limit := 50
+		if n, err := fmt.Sscanf(r.URL.Query().Get("limit"), "%d", &limit); n != 1 || err != nil || limit <= 0 {
+			limit = 50
+		}
+		if limit > 500 {
+			limit = 500
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"calls": llm.GetCalls(limit),
+			"total": len(llm.GetCalls(0)),
+		})
+	})
+
 	// 启动HTTP服务
 	srv := &http.Server{
 		Addr:    ":" + cfg.Port,