fix(query): preserve structured backend errors

apps/desktop/src/components/connection/ConnectionDialog.vue

@@ -1502,7 +1502,7 @@ function finishAgentDriverInstall() {
 function failAgentDriverInstall(error: unknown) {
   agentInstallOperationId.value = null;
   agentInstallRunning.value = false;
-  agentInstallError.value = translateBackendError(t, errorMessage(error));
+  agentInstallError.value = translateBackendError(t, error);
   showAgentInstallDialog.value = true;
 }
 
@@ -1559,7 +1559,7 @@ async function ensureRequiredAgentDriverInstalled(config: ConnectionConfig): Pro
     await refreshLocalAgentDrivers();
     finishAgentDriverInstall();
   } catch (error) {
-    testResult.value = { ok: false, message: errorMessage(error) };
+    testResult.value = { ok: false, message: translateBackendError(t, error) };
     failAgentDriverInstall(error);
     throw error;
   }
@@ -1601,7 +1601,7 @@ async function installSqlServerLegacyCompatibilityComponentIfNeeded(): Promise<b
     await refreshLocalAgentDrivers();
     finishAgentDriverInstall();
   } catch (error) {
-    testResult.value = { ok: false, message: errorMessage(error) };
+    testResult.value = { ok: false, message: translateBackendError(t, error) };
     failAgentDriverInstall(error);
     throw error;
   }

apps/desktop/src/components/editor/AiAssistant.vue

@@ -79,6 +79,7 @@ import type { ConnectionConfig, QueryTab, SavedSqlFile, TableInfo } from "@/type
 import { fetchNamespaceOptionsForConnection, useDatabaseOptions } from "@/composables/useDatabaseOptions";
 import { decodeSelectableDatabaseValue, encodeSelectableDatabaseValue, formatDatabaseLabel, resolveDefaultDatabase } from "@/lib/database/defaultDatabase";
 import { normalizeSqliteNamespace } from "@/lib/database/sqliteNamespace";
+import { isQueryExecutionErrorResult } from "@/lib/query/queryResultError";
 import { isSchemaAware } from "@/lib/database/databaseCapabilities";
 import ExplainPlanViewer from "@/components/explain/ExplainPlanViewer.vue";
 import { parseExplainResult, parseOracleExplainText, type ParsedExplainPlan } from "@/lib/diagram/explainPlan";
@@ -662,8 +663,7 @@ watch(
 function selectAction(action: AiAction) {
   activeAction.value = action;
   if (action === "fix" && props.tab?.result) {
-    const cols = props.tab.result.columns;
-    if (cols.includes("Error")) {
+    if (isQueryExecutionErrorResult(props.tab.result)) {
       const errVal = props.tab.result.rows[0]?.[0];
       if (errVal != null) prompt.value = String(errVal);
     }

apps/desktop/src/components/grid/DataGrid.vue

@@ -67,6 +67,7 @@ import DataGridQueryControls from "@/components/grid/DataGridQueryControls.vue";
 import TemporalCellEditor from "@/components/grid/TemporalCellEditor.vue";
 import EnumCellEditor from "@/components/grid/EnumCellEditor.vue";
 import type { QueryResult, ColumnInfo, DatabaseType, ForeignKeyInfo, IndexInfo, TriggerInfo, TableInfoTab } from "@/types/database";
+import { isQueryExecutionErrorResult } from "@/lib/query/queryResultError";
 import { tableObjectSourceKind } from "@/lib/table/tableObjectSourceKind";
 import { tableColumnDefaultDisplayValue } from "@/lib/table/tableColumnDefaultPresentation";
 import { shouldNavigateFromTableInfoColumnClick } from "@/lib/table/tableInfoColumnNavigation";
@@ -3577,7 +3578,7 @@ watch(
   },
   { immediate: true },
 );
-const isErrorResult = computed(() => props.result.columns.length === 1 && props.result.columns[0] === "Error" && props.result.rows.length > 0);
+const isErrorResult = computed(() => isQueryExecutionErrorResult(props.result) && props.result.rows.length > 0);
 const errorMessage = computed(() => (isErrorResult.value ? String(props.result.rows[0]?.[0] ?? "") : ""));
 // --- Selection composable ---
 const selection = useDataGridSelection({

apps/desktop/src/components/layout/ContentArea.vue

@@ -3,6 +3,7 @@ import { computed, ref, defineAsyncComponent, watch, nextTick, onMounted, onUnmo
 import { safeLocalStorageGet, safeLocalStorageSet } from "@/lib/backend/safeStorage";
 import { appendDebugLog, isDebugLoggingEnabled } from "@/lib/backend/debugLog";
 import { canReloadUnavailableDataTab } from "@/lib/table/tableDataRefresh";
+import { isQueryExecutionErrorResult } from "@/lib/query/queryResultError";
 import type { CSSProperties } from "vue";
 import { useI18n } from "vue-i18n";
 import { Check, Columns3Cog, EyeOff, Loader2, Search, TableProperties, ChevronDown, ChevronUp, Inbox, RefreshCcw, Wrench, Toolbox, Database, Download, Upload, X, Pin, Rows3, SquareDashed, Minus, Plus, ShieldAlert, AlignLeft, AlignRight, PanelsTopLeft } from "@lucide/vue";
@@ -340,7 +341,7 @@ const hasNumericData = computed(() => {
 
 const activeQueryError = computed(() => {
   const result = props.activeTab.result;
-  if (!result?.columns.includes("Error")) return "";
+  if (!result || !isQueryExecutionErrorResult(result)) return "";
   return String(result.rows[0]?.[0] ?? "");
 });
 const hasQueryOutput = computed(
@@ -1480,7 +1481,7 @@ defineExpose({ focusSearch, refreshData, refreshQueryEditorCompletionCache, hand
                     @export-archive="exportResultArchive"
                   />
                 </template>
-                <template v-if="activeTab.result?.columns.includes('Error')" #error-actions="{ errorMessage }">
+                <template v-if="activeTab.result && isQueryExecutionErrorResult(activeTab.result)" #error-actions="{ errorMessage }">
                   <QueryErrorActions :error-message="String(errorMessage)" :connection-id="activeTab.connectionId" @change-query-timeout="activeTab.connectionId && emit('openConnectionSettings', activeTab.connectionId, 'advanced')" @fix-with-ai="(message) => emit('fixWithAi', message)" />
                 </template>
               </DataGrid>
@@ -1777,7 +1778,7 @@ defineExpose({ focusSearch, refreshData, refreshQueryEditorCompletionCache, hand
           @paginate="(offset: number, limit: number, whereInput?: string, orderBy?: string) => emit('paginate', offset, limit, whereInput, orderBy)"
           @sort="(column: string, columnIndex: number, direction: 'asc' | 'desc' | null, whereInput?: string, mode?: DataGridSortMode) => emit('sort', column, columnIndex, direction, whereInput, mode)"
         >
-          <template v-if="activeTab.result?.columns.includes('Error')" #error-actions="{ errorMessage }">
+          <template v-if="activeTab.result && isQueryExecutionErrorResult(activeTab.result)" #error-actions="{ errorMessage }">
             <QueryErrorActions :error-message="String(errorMessage)" :connection-id="activeTab.connectionId" @change-query-timeout="activeTab.connectionId && emit('openConnectionSettings', activeTab.connectionId, 'advanced')" @fix-with-ai="(message) => emit('fixWithAi', message)" />
           </template>
         </DataGrid>