Remove non-browser e2e test infrastructure

- Delete .github/workflows/e2e.yaml
- Delete playwright.config.ts
- Delete e2e/ directory (auth.setup.ts, kube-vip.spec.ts)
- Delete scripts/deploy-e2e-headlamp.sh and teardown-e2e-headlamp.sh
- Remove e2e and e2e:headed scripts from package.json
- Remove @playwright/test devDependency

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

package.json

@@ -23,9 +23,7 @@
     "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"
   },
   "peerDependencies": {
     "react": "^18.0.0",
@@ -55,7 +53,6 @@
     "react-dom": "^18.3.1",
     "react-router-dom": "^5.3.0",
     "typescript": "~5.6.2",
-    "vitest": "^3.2.4",
-    "@playwright/test": "^1.58.2"
+    "vitest": "^3.2.4"
   }
 }