chore: remove E2E testing and fix CI pnpm build errors

Delete all non-browser E2E testing infrastructure (board directive).
Fix ERR_PNPM_IGNORED_BUILDS by adding pnpm.onlyBuiltDependencies.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

package.json

@@ -22,15 +22,12 @@
     "format": "prettier --write src/",
     "format:check": "prettier --check src/",
     "test": "vitest run",
-    "test:watch": "vitest",
-    "e2e": "playwright test",
-    "e2e:headed": "playwright test --headed"
+    "test:watch": "vitest"
   },
   "devDependencies": {
     "@headlamp-k8s/eslint-config": "^0.6.0",
     "@kinvolk/headlamp-plugin": "^0.13.0",
     "@mui/material": "^5.15.14",
-    "@playwright/test": "^1.58.2",
     "@testing-library/jest-dom": "^6.4.8",
     "@testing-library/react": "^16.0.0",
     "@testing-library/user-event": "^14.5.2",
@@ -52,5 +49,12 @@
     "vite": ">=6.4.2",
     "lodash": ">=4.18.0",
     "elliptic": ">=6.6.1"
+  },
+  "pnpm": {
+    "onlyBuiltDependencies": [
+      "@swc/core",
+      "esbuild",
+      "msw"
+    ]
   }
 }