test(e2e): walking-skeleton Playwright happy path + verify-e2e lane (refs #68)

tests/e2e Playwright spec drives DigiD login (jan-burger/test123) → submit →
confirmation against the compose-served portal. run-e2e-check.sh runs it inside the
compose network (node container, browser installed at runtime) so the token issuer
(keycloak:8080) matches the BFF authority (ADR-0010). Wired as verify-e2e (Makefile +
verify chain + a verify-stack CI step).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -124,6 +124,8 @@ jobs:
         run: make verify-domain
       - name: BFF → Keycloak + domain + projection
         run: make verify-bff
+      - name: Self-service e2e (Playwright, login → submit → success)
+        run: make verify-e2e
       # Log dump must precede teardown (which removes the containers).
       - name: Dump container logs on failure
         if: failure()