fix: platform_silent记忆提取 + 群聊上下文整合 + 多QQ实例支持

- platform_silent模式接入Orchestrator记忆提取：被动观察群聊时提取值得记住的信息到对应命名空间
- post_chat后台思考注入平台观察：对话后思考也能看到群聊摘要
- QQ适配器：OneBot v11 self_id动态捕获、CQ图片URL提取、视觉+OCR并行处理
- Router解耦：ConfigName/PlatformName分离，支持多QQ实例独立连接
- 黑白名单功能：后端API + Ethend代理 + UI面板
- \n\n双换行断句：AI回复按双换行分割为多条消息按间隔发送
- @提及修复：bot自感知UID进行@检测
- 群聊上下文共享：channel-based userID避免记忆碎片化
- 消息日志显示处理后内容而非原始SSE数据
- platform-bridge Dockerfile + docker-compose.yml更新

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

backend/platform-bridge/internal/bridge/unified.go

@@ -21,6 +21,12 @@ type UnifiedMessage struct {
 
 	RawData   interface{} `json:"raw_data,omitempty"`
 	Timestamp time.Time   `json:"timestamp"`
+
+	// Routing metadata.
+	RouteType         string      `json:"route_type,omitempty"`          // "normal", "silent", "admin_mention"
+	OriginalSenderUID string      `json:"original_sender_uid,omitempty"` // preserved before identity mapping
+	OriginalRawMessage interface{} `json:"-"`                             // preserved for SendMessage wiring
+	BotUID            string      `json:"-"`                             // bot's own platform UID, set by router
 }
 
 // Attachment represents a file/image/voice attachment.