fix(desktop): scope account access to owning client and extend identity verification

Restrict account tracking, probing, and health reporting to accounts owned
by the current client (client_id match). Extend identity-match verification
to bilibili, juejin, and smzdm so session validity is confirmed locally
rather than deferred to remote health state. Server-side account view now
uses stored client_id as authoritative owner instead of presence data.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/internal/tenant/app/desktop_account_service.go

@@ -557,26 +557,19 @@ func (s *DesktopAccountService) buildDesktopAccountView(
 	var clientLastSeenAt *time.Time
 	var clientDeviceName *string
 
-	resolvedClientID := account.ClientID
-	if presenceClientMap != nil {
-		if activeClientID, ok := presenceClientMap[account.DesktopID]; ok {
-			resolvedClientID = &activeClientID
-		}
-	}
-
-	if resolvedClientID != nil {
-		value := resolvedClientID.String()
+	if account.ClientID != nil {
+		value := account.ClientID.String()
 		clientID = &value
 
 		online := false
 		clientOnline = &online
 
 		if clientMap != nil {
-			if client, ok := clientMap[*resolvedClientID]; ok && client != nil {
+			if client, ok := clientMap[*account.ClientID]; ok && client != nil {
 				clientLastSeenAt = client.LastSeenAt
 				clientDeviceName = client.DeviceName
 				if presenceClientMap != nil {
-					if activeClientID, ok := presenceClientMap[account.DesktopID]; ok && activeClientID == *resolvedClientID {
+					if activeClientID, ok := presenceClientMap[account.DesktopID]; ok && activeClientID == *account.ClientID {
 						online = true
 					}
 				}