feat: QQ主动消息管道 + 戳一戳事件 + thinker提示词优化

- ProactiveTarget 结构体 + QQ目标正则解析（extractProactiveMessage 返回双值）
- storeThought 双路推送：platform消息 → platformMessagePusher，web消息 → messagePusher
- platform-bridge: SendProactive接口 + ProactiveSender + /api/v1/internal/send-proactive端点
- QQ戳一戳/notice事件 → noticeToUnified → ContentType "action"
- thinker提示词注入QQ频道上下文：群名称(群号)、活跃时间、trigger-aware引导
- SetBotUID/SetPlatformMessagePusher/AddOrUpdatePlatformChannel 方法
- ai-core source 增加 BotUID/GroupName，platform-bridge source 增加 bot_uid/group_name
- 支持 [CQ:at,qq=xxx] @提及标签自动拼接

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

backend/platform-bridge/internal/adapter/qq/protocol.go

@@ -26,7 +26,17 @@ type OBv11Message struct {
 	MessageSeq int64         `json:"message_seq"`
 
 	// Notice fields.
-	NoticeType string        `json:"notice_type"`
+	NoticeType string `json:"notice_type"`
+
+	// Poke detail (sub_type === "poke").
+	PokeDetail *OBv11PokeDetail `json:"poke_detail,omitempty"`
+}
+
+// OBv11PokeDetail contains extra info for poke ("戳一戳") notice events.
+type OBv11PokeDetail struct {
+	Action   string `json:"action"`   // e.g. "戳了戳"
+	Suffix   string `json:"suffix"`   // e.g. "你的脸蛋"
+	PokePic  string `json:"poke_pic"` // e.g. "https://..."
 }
 
 // OBv11Sender represents a message sender.