feat(redis): implement Pub/Sub support for usage tracking

- Added Redis Pub/Sub capability to broadcast usage updates to subscribed clients.
- Enhanced `redisqueue` with subscriber management and message broadcasting.
- Updated tests to validate Pub/Sub message handling, subscription behavior, and fallback to the queue after unsubscribing.
- Integrated `project_id` parsing into auth-files logic to include project identifiers in metadata.

Closes: #3027

internal/api/handlers/management/oauth_sessions.go

@@ -190,6 +190,21 @@ func IsOAuthSessionPending(state, provider string) bool {
 	return oauthSessions.IsPending(state, provider)
 }
 
+func oauthSessionErrorWithCause(message string, cause error) string {
+	message = strings.TrimSpace(message)
+	if message == "" {
+		message = "Authentication failed"
+	}
+	if cause == nil {
+		return message
+	}
+	detail := strings.TrimSpace(cause.Error())
+	if detail == "" {
+		return message
+	}
+	return message + ": " + detail
+}
+
 func ValidateOAuthState(state string) error {
 	trimmed := strings.TrimSpace(state)
 	if trimmed == "" {