fix: use dedicated error message for AI Models card load failure (Task 9 review)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/src/locales/en.ts

@@ -116,6 +116,7 @@ export interface Translations {
     labelChunkBackend: string;
     labelParserFailureMode: string;
     configLoadError: string;
+    modelsLoadError: string;
     cardBreakdown: string;
     breakdownIndexed: string;
     breakdownProcessing: string;
@@ -357,6 +358,7 @@ export const en: Translations = {
     labelChunkBackend: 'Chunk backend',
     labelParserFailureMode: 'Parser failure mode',
     configLoadError: 'Could not load config',
+    modelsLoadError: 'Could not load model status',
     cardBreakdown: 'Document breakdown',
     breakdownIndexed: 'Indexed',
     breakdownProcessing: 'Processing / Parsed',

frontend/src/locales/zh.ts

@@ -117,6 +117,7 @@ export const zh: Translations = {
     labelChunkBackend: '分块后端',
     labelParserFailureMode: '解析失败模式',
     configLoadError: '无法加载配置',
+    modelsLoadError: '无法加载模型状态',
     cardBreakdown: '文档分布',
     breakdownIndexed: '已索引',
     breakdownProcessing: '处理中 / 已解析',

frontend/src/pages/Status/StatusPage.tsx

@@ -340,7 +340,7 @@ export function StatusPage() {
                   );
                 })
               ) : (
-                <div style={{ padding: '12px 0', color: 'var(--muted)', fontSize: 13 }}>{t.status.configLoadError}</div>
+                <div style={{ padding: '12px 0', color: 'var(--muted)', fontSize: 13 }}>{t.status.modelsLoadError}</div>
               )}
             </div>