fix: add explicit dev dependencies and fix React test environment (#11)

* fix: add explicit dev dependencies and fix React test environment

- Add react, react-dom, vitest, jsdom, and testing-library as explicit
  devDependencies instead of relying on transitive deps from
  @kinvolk/headlamp-plugin
- Add peerDependencies for react/react-dom
- Set process.env.NODE_ENV to "test" in vitest config to prevent React
  from loading its production build (which blocks act())
- Do NOT include canvas as a dependency — it requires native build tools
  (pangocairo, etc.) not present in the CI node:22 container

Fixes CI install failures from prior PR #10 which included canvas.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: add react-router-dom devDep and remove unused vite types

- Add react-router-dom as explicit devDependency to fix
  ServicesPage.test.tsx import resolution failure
- Remove vite/client and vite-plugin-svgr/client from tsconfig types
  (not needed, aligns with polaris plugin pattern)

Addresses QA review feedback on PR#11.

---------

Co-authored-by: gandalf-the-greybeard[bot] <gandalf-the-greybeard[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

vitest.config.mts

@@ -1,6 +1,9 @@
 import { defineConfig } from 'vitest/config';
 
 export default defineConfig({
+  define: {
+    'process.env.NODE_ENV': '"test"',
+  },
   test: {
     globals: true,
     environment: 'jsdom',