refactor: 彻底消除硬编码 qq — 平台标识统一为 obv11

- PlatformName() 返回 "obv11"
- platformFormats key: "obv11"
- 所有 platform == "qq" 检查 → "obv11"
- session prefix: platform_qq_ → platform_obv11_
- env var PLATFORM_CHANNELS: obv11:group:xxx
- ethend 平台标识同步更新
- 注释和测试用例同步

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

backend/platform-bridge/cmd/main.go

@@ -300,14 +300,14 @@ func main() {
 			// Sync admin identities from config fields.
 			syncAdminUIDs(mapper, platform, fields, cfg.AdminNickname)
 			// Restart OBv11 reader when OBv11 config changes.
-			if platform == "qq" {
+			if platform == "obv11" {
 				startOBv11Readers(router)
 			}
 		} else {
 			router.RemoveAdapter(name)
 			fmt.Printf("Platform adapter removed: %s\n", name)
 			// Cancel reader goroutines for removed adapter.
-			if platform == "qq" {
+			if platform == "obv11" {
 				startOBv11Readers(router)
 			}
 		}
@@ -366,7 +366,7 @@ func startOBv11Readers(router *bridge.PlatformRouter) {
 	qqReaderCancels = make(map[string]context.CancelFunc)
 	qqReaderCancelsMu.Unlock()
 
-	for _, qqa := range router.GetAdaptersByPlatform("qq") {
+	for _, qqa := range router.GetAdaptersByPlatform("obv11") {
 		qqAdapter, ok := qqa.(*qqadapter.Adapter)
 		if !ok {
 			continue
@@ -485,7 +485,7 @@ func createAdapters(cfg *config.Config, store *config.Store) []bridge.PlatformAd
 	}
 
 	// Seed default adapters for platforms that have no stored config.
-	defaultPlatforms := []string{"qq", "telegram", "webhook", "wechat", "feishu", "discord"}
+	defaultPlatforms := []string{"obv11", "telegram", "webhook", "wechat", "feishu", "discord"}
 	for _, name := range defaultPlatforms {
 		if seen[name] {
 			continue
@@ -500,10 +500,10 @@ func createAdapters(cfg *config.Config, store *config.Store) []bridge.PlatformAd
 }
 
 // createSingleAdapter creates one platform adapter from config fields.
-// platform is the base platform type ("qq", "telegram", etc.), configName is the instance key.
+// platform is the base platform type ("obv11", "telegram", etc.), configName is the instance key.
 func createSingleAdapter(cfg *config.Config, platform, configName, configID string, fields map[string]string) bridge.PlatformAdapter {
 	switch platform {
-	case "qq":
+	case "obv11":
 		port := cfg.OBv11BotPort
 		if p, ok := fields["bot_port"]; ok && p != "" {
 			port = p
@@ -565,7 +565,7 @@ func mergeFields(cfg *config.Config, platform string, stored *config.PlatformCon
 	if fields["webhook_url"] == "" && cfg.TelegramWebhookURL != "" && platform == "telegram" {
 		fields["webhook_url"] = cfg.TelegramWebhookURL
 	}
-	if fields["bot_port"] == "" && cfg.OBv11BotPort != "" && platform == "qq" {
+	if fields["bot_port"] == "" && cfg.OBv11BotPort != "" && platform == "obv11" {
 		fields["bot_port"] = cfg.OBv11BotPort
 	}
 	return fields
@@ -989,7 +989,7 @@ func seedIdentities(m *bridge.IdentityMapper, store *config.Store, adminNickname
 	}
 
 	// From stored platform configs (admin_uids field).
-	for _, name := range []string{"qq", "telegram", "webhook", "wechat", "feishu", "discord"} {
+	for _, name := range []string{"obv11", "telegram", "webhook", "wechat", "feishu", "discord"} {
 		stored, _ := store.Get(name)
 		if stored == nil {
 			continue