fix: Wrap MobileLayout with I18nProvider; use outputLanguage key in config

P1: MobileLayout was missing I18nProvider wrapper, causing useI18n
    to throw error on mobile devices. Now both desktop and mobile
    layouts are wrapped with I18nProvider.

P2: SKILL.md used 'language' key but Dashboard reads 'outputLanguage'.
    Fixed config.json key name to match ProjectConfig type definition.

All tests passed:
- Core: 670 tests
- Dashboard: 42 tests

understand-anything-plugin/packages/dashboard/src/App.tsx

@@ -394,16 +394,18 @@ function Dashboard({ accessToken }: { accessToken: string }) {
 
   if (isMobile) {
     return (
-      <ThemeProvider metaTheme={metaTheme}>
-        <MobileLayout
-          accessToken={accessToken}
-          showKeyboardHelp={showKeyboardHelp}
-          setShowKeyboardHelp={setShowKeyboardHelp}
-          loadError={loadError}
-          allIssues={allIssues}
-          shortcuts={shortcuts}
-        />
-      </ThemeProvider>
+      <I18nProvider language={outputLanguage ?? "en"}>
+        <ThemeProvider metaTheme={metaTheme}>
+          <MobileLayout
+            accessToken={accessToken}
+            showKeyboardHelp={showKeyboardHelp}
+            setShowKeyboardHelp={setShowKeyboardHelp}
+            loadError={loadError}
+            allIssues={allIssues}
+            shortcuts={shortcuts}
+          />
+        </ThemeProvider>
+      </I18nProvider>
     );
   }
 

understand-anything-plugin/skills/understand/SKILL.md

@@ -121,10 +121,10 @@ Determine whether to run a full analysis or incremental update.
       - `chinese` → `zh`, `japanese` → `ja`, `korean` → `ko`, `english` → `en`, `spanish` → `es`, `french` → `fr`, `german` → `de`, `portuguese` → `pt`, `russian` → `ru`, `arabic` → `ar`, etc.
       - Locale variants: `zh-TW`, `zh-HK`, `zh-CN`, `pt-BR`, etc. are preserved as-is.
     - If `--language` is NOT specified:
-      - Check `$PROJECT_ROOT/.understand-anything/config.json` for an existing `language` field. If present, use that.
+      - Check `$PROJECT_ROOT/.understand-anything/config.json` for an existing `outputLanguage` field. If present, use that.
       - If no stored preference, default to `en` (English).
     - If `--language` IS specified:
-      - Update `$PROJECT_ROOT/.understand-anything/config.json` with the new language: merge `{"language": "<lang>"}` into existing config.
+      - Update `$PROJECT_ROOT/.understand-anything/config.json` with the new language: merge `{"outputLanguage": "<lang>"}` into existing config.
       - Store as `$OUTPUT_LANGUAGE` for use throughout all phases.
     - **Language directive template:** Store as `$LANGUAGE_DIRECTIVE`:
       ```markdown