fix: use token auth in E2E workflow, handle direct /token redirect

The E2E Headlamp instance is deployed without OIDC configuration, so
Headlamp redirects / → /token directly instead of / → /login. The
authenticateWithToken function was hardcoded to expect /login first,
causing a 60s timeout on every run.

- e2e.yaml: remove unused Setup Helm step (deploy script uses kubectl)
- e2e.yaml: remove AUTHENTIK_USERNAME/PASSWORD (no OIDC in E2E instance)
- auth.setup.ts: waitForURL accepts both /login and /token; only clicks
  "use a token" if landed on /login (OIDC-configured Headlamp)

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

.github/workflows/e2e.yaml

@@ -32,9 +32,6 @@ jobs:
       - name: Setup kubectl
         uses: azure/setup-kubectl@v4
 
-      - name: Setup Helm
-        uses: azure/setup-helm@v4
-
       - name: Install dependencies
         run: npm ci
 
@@ -61,8 +58,6 @@ jobs:
         env:
           HEADLAMP_URL: ${{ env.HEADLAMP_URL }}
           HEADLAMP_TOKEN: ${{ env.HEADLAMP_TOKEN }}
-          AUTHENTIK_USERNAME: ${{ secrets.AUTHENTIK_USERNAME }}
-          AUTHENTIK_PASSWORD: ${{ secrets.AUTHENTIK_PASSWORD }}
 
       - name: Teardown E2E instance
         if: always()