fix(ops): match "insufficient account balance" in error filter

The upstream Gemini API returns "Insufficient account balance" which
doesn't contain the substring "insufficient balance". Add explicit
match for the full phrase to ensure the filter works correctly.

backend/internal/handler/ops_error_logger.go

@@ -33,6 +33,7 @@ const (
 	opsErrInvalidAPIKey       = "invalid_api_key"
 	opsErrAPIKeyRequired      = "api_key_required"
 	opsErrInsufficientBalance        = "insufficient balance"
+	opsErrInsufficientAccountBalance = "insufficient account balance"
 	opsErrInsufficientQuota          = "insufficient_quota"
 
 	// 上游错误码常量 — 错误分类 (normalizeOpsErrorType / classifyOpsPhase / classifyOpsIsBusinessLimited)
@@ -1233,8 +1234,9 @@ func shouldSkipOpsErrorLog(ctx context.Context, ops *service.OpsService, message
 
 	// Check if insufficient balance errors should be ignored
 	if settings.IgnoreInsufficientBalanceErrors {
-		if strings.Contains(bodyLower, opsErrInsufficientBalance) || strings.Contains(bodyLower, opsErrInsufficientQuota) ||
-			strings.Contains(msgLower, opsErrInsufficientBalance) {
+		if strings.Contains(bodyLower, opsErrInsufficientBalance) || strings.Contains(bodyLower, opsErrInsufficientAccountBalance) ||
+			strings.Contains(bodyLower, opsErrInsufficientQuota) ||
+			strings.Contains(msgLower, opsErrInsufficientBalance) || strings.Contains(msgLower, opsErrInsufficientAccountBalance) {
 			return true
 		}
 	}