Add wxDataViewCtrl, wxHtmlWindow, and wxStyledTextCtrl test apps

Test 3 previously untested KiCad-critical wxWidgets controls:
- wxDataViewCtrl: List/tree views for Zone Manager, Net Inspector (10 tests)
- wxHtmlWindow: HTML rendering for About dialogs, error formatting (8 tests)
- wxStyledTextCtrl: Syntax highlighting for DRC rules, Python console (10 tests)

Also add button-finder config and update docs. All 119 tests passing.

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

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

tests/playwright-button-finder.config.ts

@@ -0,0 +1,35 @@
+import { defineConfig, devices } from '@playwright/test';
+
+/**
+ * Playwright config for button-finder utility ONLY.
+ * This config does NOT exclude button-finder.spec.ts like the main config.
+ */
+export default defineConfig({
+  testDir: './e2e',
+  fullyParallel: false,
+  retries: 0,
+  workers: 1,
+  reporter: 'list',
+  timeout: 300000,  // 5 minute timeout for scanning
+
+  // Only include the button-finder test
+  testMatch: '**/button-finder.spec.ts',
+
+  use: {
+    baseURL: 'http://localhost:8080',
+    trace: 'off',
+  },
+
+  projects: [
+    {
+      name: 'chromium',
+      use: { ...devices['Desktop Chrome'] },
+    },
+  ],
+
+  webServer: {
+    command: 'npx serve wasm-app -p 8080',
+    port: 8080,
+    reuseExistingServer: true,
+  },
+});