fix: add testing-library/jest-dom matchers for UI tests

- Add @testing-library/jest-dom as dev dependency
- Create test-setup.ts to import jest-dom matchers
- Configure Vitest to use setup file
- All UI package tests now passing

Fixes test failures with toHaveTextContent and other DOM matchers.

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

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

packages/ui/package.json

@@ -32,10 +32,11 @@
     "@tpmjs/utils": "workspace:*"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.0",
     "@tpmjs/eslint-config": "workspace:*",
     "@tpmjs/test": "workspace:*",
     "@tpmjs/tsconfig": "workspace:*",
-    "@testing-library/react": "^16.3.0",
     "@types/react": "^19.0.2",
     "@types/react-dom": "^19.0.2",
     "happy-dom": "^15.11.7",

packages/ui/src/test-setup.ts

@@ -0,0 +1 @@
+import '@testing-library/jest-dom/vitest';

packages/ui/vitest.config.ts

@@ -4,5 +4,6 @@ export default defineConfig({
   test: {
     globals: true,
     environment: 'happy-dom',
+    setupFiles: ['./src/test-setup.ts'],
   },
 });