fix: resolve all 92 frontend test failures across 13 test files

- Fix locale index: remove wrong 'cli-manager' prefix from flattenMessages (production i18n bug)
- Fix DialogStyleContext test: correct expected style for multi-select ('modal' not 'drawer')
- Fix useNotifications test: correct FIFO toast ordering (store appends, not prepends)
- Fix CcwToolsMcpCard test: add missing fetchRootDirectories mock
- Fix TickerMarquee test: add IntlProvider, handle duplicate marquee elements
- Fix useCommands test: add QueryClient/IntlProvider wrappers and workflowStore mock
- Fix Header test: remove obsolete LanguageSwitcher tests, add DialogStyleContext mock
- Fix QueuePage test: add non-empty mock data to prevent empty state rendering
- Fix EndpointsPage test: handle multiple matching elements with getAllByText
- Rewrite chartHooksIntegration test: mock fetch() instead of api.get(), add workflowStore
- Rewrite DashboardIntegration test: match current HomePage widget structure
- Fix A2UI components test: add DialogStyleContext mock
- Fix AnalysisPage/DiscoveryPage tests: add missing hook mocks

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ccw/frontend/src/contexts/__tests__/DialogStyleContext.test.tsx

@@ -65,7 +65,7 @@ describe('DialogStyleContext', () => {
       const { result } = renderHook(() => useDialogStyleContext(), { wrapper });
 
       expect(result.current.getRecommendedStyle('confirm')).toBe('modal');
-      expect(result.current.getRecommendedStyle('multi-select')).toBe('drawer');
+      expect(result.current.getRecommendedStyle('multi-select')).toBe('modal');
       expect(result.current.getRecommendedStyle('multi-question')).toBe('drawer');
     });