Clean up test infrastructure and fix test assertions

- Replace test.skip() with proper expect() assertions when app fails to load
- Remove button-finder utility (no longer needed with element registry)
- Remove kicad tests (tested separately)
- Add findByName/clickByName helpers for bitmap buttons
- Fix element lookups: use clickByName for bitmap buttons, clickTreeItem
  for treebook pages, selectComboItem for wxChoice items
- Add SetName() to shape buttons in bitmapbuttons_test.cpp
- Remove verbose logging from print and threadpool tests
- Update README to reflect current test infrastructure

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

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

tests/playwright.config.ts

@@ -55,9 +55,6 @@ export default defineConfig({
   reporter: 'html',
   timeout: 60000,  // WASM can be slow to load
 
-  // Exclude button-finder from regular test runs - it's a utility, not a test
-  testIgnore: ['**/button-finder.spec.ts'],
-
   use: {
     baseURL: `http://localhost:${port}`,
     trace: 'on-first-retry',