test(frontend): comprehensive test coverage improvements and bug fixes

- Raise coverage thresholds to 90% statements/lines/functions, 85% branches
- Add comprehensive tests for ProjectDashboard, ProjectWizard, and all wizard steps
- Add tests for issue management: IssueDetailPanel, BulkActions, IssueFilters
- Expand IssueTable tests with keyboard navigation, dropdown menu, edge cases
- Add useIssues hook tests covering all mutations and optimistic updates
- Expand eventStore tests with selector hooks and additional scenarios
- Expand useProjectEvents tests with error recovery, ping events, edge cases
- Add PriorityBadge, StatusBadge, SyncStatusIndicator fallback branch tests
- Add constants.test.ts for comprehensive constant validation

Bug fixes:
- Fix false positive rollback test to properly verify onMutate context setup
- Replace deprecated substr() with substring() in mock helpers
- Fix type errors: ProjectComplexity, ClientMode enum values
- Fix unused imports and variables across test files
- Fix @ts-expect-error directives and method override signatures

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/tests/features/issues/components/PriorityBadge.test.tsx

@@ -23,4 +23,18 @@ describe('PriorityBadge', () => {
     const badge = screen.getByText('High');
     expect(badge).toHaveClass('custom-class');
   });
+
+  it('renders critical priority', () => {
+    render(<PriorityBadge priority="critical" />);
+
+    expect(screen.getByText('Critical')).toBeInTheDocument();
+  });
+
+  it('falls back to medium config for unknown priority', () => {
+    // @ts-expect-error - Testing unknown priority value
+    render(<PriorityBadge priority="unknown-priority" />);
+
+    // Should fall back to medium config
+    expect(screen.getByText('Medium')).toBeInTheDocument();
+  });
 });