支持工具调用：三个AI角色配置、工具注册表与流式工具轮

internal/tools/time_tool.go

@@ -0,0 +1,38 @@
+package tools
+
+import (
+	"encoding/json"
+	"time"
+)
+
+type TimeTool struct{}
+
+func (TimeTool) Name() string { return "get_current_time" }
+func (TimeTool) Description() string {
+	return "获取当前日期和时间，可选指定时区（如 Asia/Shanghai，默认本地时区）"
+}
+func (TimeTool) Parameters() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"timezone": map[string]any{"type": "string", "description": "IANA 时区名，如 Asia/Shanghai"},
+		},
+	}
+}
+
+func (TimeTool) Execute(args json.RawMessage) (string, error) {
+	var p struct {
+		Timezone string `json:"timezone"`
+	}
+	_ = json.Unmarshal(args, &p)
+	loc := time.Local
+	if p.Timezone != "" {
+		l, err := time.LoadLocation(p.Timezone)
+		if err != nil {
+			return "", err
+		}
+		loc = l
+	}
+	now := time.Now().In(loc)
+	return now.Format("2006-01-02 15:04:05 Monday MST"), nil
+}