feat: 群聊提醒 — 提醒关联平台/频道/适配器，到期发回原群聊

- reminder_create 新增 platform/channel_type/channel_id/adapter_name 参数
- Gateway Reminder 模型 + DB 迁移 + CRUD 全部支持新字段
- 提醒到期时：群聊提醒 → platform-bridge 发回原群聊
- 非群聊提醒 → 走 Web 端推送
- Thinker 新增 PushPlatformMessage 方法

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

backend/ai-core/internal/background/thinker.go

@@ -397,6 +397,17 @@ func (t *Thinker) TriggerReminderMessage(userID, sessionID, message string) {
 	}
 }
 
+// PushPlatformMessage pushes a message to a platform channel via the platform pusher.
+func (t *Thinker) PushPlatformMessage(target ProactiveTarget, message string) {
+	t.mu.Lock()
+	pusher := t.platformMessagePusher
+	t.mu.Unlock()
+	if pusher != nil {
+		log.Printf("[平台推送] target=%s/%s group=%s msg=%s", target.Platform, target.ChatType, target.GroupID, message)
+		pusher(target, message)
+	}
+}
+
 // ThinkerConfig 后台思考配置
 type ThinkerConfig struct {
 	Enabled          bool

backend/ai-core/internal/tools/gateway_client.go

@@ -38,7 +38,7 @@ type Reminder struct {
 }
 
 // CreateReminder calls POST /api/v1/internal/reminders on the Gateway.
-func (c *GatewayClient) CreateReminder(ctx context.Context, userID, title, description, remindAt, repeatType, sessionID string) (*Reminder, error) {
+func (c *GatewayClient) CreateReminder(ctx context.Context, userID, title, description, remindAt, repeatType, sessionID, platform, channelType, channelID, adapterName string) (*Reminder, error) {
 	body := map[string]interface{}{
 		"user_id":     userID,
 		"title":       title,
@@ -46,6 +46,10 @@ func (c *GatewayClient) CreateReminder(ctx context.Context, userID, title, descr
 		"remind_at":   remindAt,
 		"repeat_type": repeatType,
 		"session_id":  sessionID,
+		"platform":     platform,
+		"channel_type": channelType,
+		"channel_id":   channelID,
+		"adapter_name": adapterName,
 	}
 	reqBody, _ := json.Marshal(body)
 

backend/ai-core/internal/tools/reminder_tool.go

@@ -20,7 +20,7 @@ func NewReminderCreateTool(gw *GatewayClient, adminID string) *ReminderCreateToo
 func (t *ReminderCreateTool) Definition() ToolDefinition {
 	return ToolDefinition{
 		Name:        "reminder_create",
-		Description: "创建一个定时提醒。可用于提醒用户做某事、定时通知等。支持重复类型（none/daily/weekly/monthly）。时间格式为 ISO8601（如 2026-06-23T08:00:00+08:00）。",
+		Description: "创建一个定时提醒。时间格式为 ISO8601（如 2026-06-23T08:00:00+08:00）。如果在群聊中创建提醒，请传入 platform/channel_id/channel_type/adapter_name 以便提醒时发回原群聊。",
 		Parameters: map[string]interface{}{
 			"type": "object",
 			"properties": map[string]interface{}{
@@ -28,6 +28,10 @@ func (t *ReminderCreateTool) Definition() ToolDefinition {
 				"description": map[string]string{"type": "string", "description": "提醒详细描述（可选）"},
 				"remind_at":   map[string]string{"type": "string", "description": "提醒时间，ISO8601 格式，如 2026-06-23T08:00:00+08:00"},
 				"repeat_type": map[string]string{"type": "string", "description": "重复类型：none（不重复）, daily（每天）, weekly（每周）, monthly（每月），默认 none"},
+				"platform":     map[string]string{"type": "string", "description": "（群聊提醒时必填）平台类型，如 obv11"},
+				"channel_type": map[string]string{"type": "string", "description": "（群聊提醒时必填）频道类型：group"},
+				"channel_id":   map[string]string{"type": "string", "description": "（群聊提醒时必填）群号"},
+				"adapter_name": map[string]string{"type": "string", "description": "（群聊提醒时必填）适配器名，如 obv11-main"},
 			},
 			"required": []string{"title", "remind_at"},
 		},
@@ -47,7 +51,11 @@ func (t *ReminderCreateTool) Execute(ctx context.Context, args map[string]interf
 		return &ToolResult{Success: false, Error: "title 和 remind_at 为必填项"}, nil
 	}
 
-	reminder, err := t.gw.CreateReminder(ctx, t.adminID, title, description, remindAt, repeatType, "")
+	platform, _ := args["platform"].(string)
+	channelType, _ := args["channel_type"].(string)
+	channelID, _ := args["channel_id"].(string)
+	adapterName, _ := args["adapter_name"].(string)
+	reminder, err := t.gw.CreateReminder(ctx, t.adminID, title, description, remindAt, repeatType, "", platform, channelType, channelID, adapterName)
 	if err != nil {
 		return &ToolResult{Success: false, Error: err.Error()}, nil
 	}