fix: add missing lucide-react icons for mobile-tab-bar

- Add Briefcase and Package icons
- Update mobile-tab-bar.test.tsx to use data-testid selector
- Fix ESLint errors in mobile-tab-bar.test.tsx
- Test pass rate now at 97.3% (1462/1502)

src/__mocks__/shared-mocks.tsx

@@ -109,6 +109,8 @@ export const mockLucideReact = () => {
     LogOut: () => <span data-testid="logout-icon" />,
     Home: () => <span data-testid="home-icon" />,
     FileText: () => <span data-testid="file-text-icon" />,
+    Briefcase: () => <span data-testid="briefcase-icon" />,
+    Package: () => <span data-testid="package-icon" />,
     Image: () => <span data-testid="image-icon" />,
     Save: () => <span data-testid="save-icon" />,
     Trash2: () => <span data-testid="trash-icon" />,