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/e2e/print.spec.ts

@@ -150,9 +150,8 @@ test.describe('wxPrinting Tests', () => {
       log.includes('PRINTOUT_CALLBACK')
     );
 
-    // Log what callbacks we found (for debugging)
-    console.log('Printout callbacks found:', callbacks.length);
-    callbacks.forEach(cb => console.log('  -', cb));
+    // Verify printout callbacks were triggered
+    expect(callbacks.length).toBeGreaterThan(0);
   });
 
   test('No JavaScript errors during print operations', async ({ page, testLogger }) => {