feat(core-ui): add jsdom Vitest config + RTL tests for components

Adopts jsdomVitestConfig from @repo/core-typescript. Adds
@testing-library/react, @testing-library/user-event, jsdom devDeps.
Writes smoke + interaction tests for every atom/molecule/organism/template
using renderWithProviders from @repo/core-testing/react.

Components covered:
- atoms: Button (5 tests), Input (4), Label (2)
- molecules: FormField (5)
- organisms / templates: empty barrels, no components

Adjustments:
- core-ui/tsconfig.json now extends react-library.json (jsx: react-jsx)
  with rootDir "." + paths {"@/*"} + types [vitest/globals, jest-dom]
- core-typescript/vitest.base.jsdom.ts uses ./vitest.base.node.ts (explicit
  .ts extension) so Node's ESM resolver finds the source file when loaded
  via the package export from a downstream package

Spec: §6.1, §6.5

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pnpm-lock.yaml

@@ -545,15 +545,33 @@ importers:
       '@repo/core-eslint':
         specifier: workspace:*
         version: link:../core-eslint
+      '@repo/core-testing':
+        specifier: workspace:*
+        version: link:../core-testing
       '@repo/core-typescript':
         specifier: workspace:*
         version: link:../core-typescript
       '@storybook/react':
         specifier: ^8.6.0
         version: 8.6.18(react-dom@19.2.4(react@19.2.4))(react@19.2.4)(storybook@8.6.18(prettier@3.8.1))(typescript@5.9.3)
+      '@testing-library/jest-dom':
+        specifier: ^6.5.0
+        version: 6.9.1
+      '@testing-library/react':
+        specifier: ^16.0.0
+        version: 16.3.2(@testing-library/dom@10.4.1)(@types/react-dom@19.2.3(@types/react@19.2.14))(@types/react@19.2.14)(react-dom@19.2.4(react@19.2.4))(react@19.2.4)
+      '@testing-library/user-event':
+        specifier: ^14.5.0
+        version: 14.6.1(@testing-library/dom@10.4.1)
       '@types/react':
         specifier: ^19.0.0
         version: 19.2.14
+      jsdom:
+        specifier: ^25.0.0
+        version: 25.0.1
+      vitest:
+        specifier: ^3.0.0
+        version: 3.2.4(@types/debug@4.1.13)(@types/node@25.5.2)(happy-dom@20.8.9)(jiti@2.6.1)(jsdom@25.0.1)(lightningcss@1.32.0)(sass@1.99.0)(tsx@4.21.0)
 
   packages/marketing-pages:
     dependencies: