- Remove remaining test non-null assertions and delete the broad test override
- Add explicit guards for canvas, design panel, auto-layout, SVG, Kiwi, hit-test, scene graph, text editor, and clipboard tests
- Validate check plus affected engine and E2E coverage
- Remove stale imports and unused locals from split engine and e2e tests
- Drop the targeted no-unused-vars test allowances
- Keep check and affected test suites warning-free
- Move top-level engine and e2e prefixed test files under domain folders
- Update fixture path helpers after moving render and pen tests
- Add lint coverage to prevent new top-level prefixed test files
- Refresh testing docs for the new fig and layout paths
