fix(e2e): migrate E2E namespace from privilegedescalation-dev to headlamp-dev (#130)

The E2E workflow and deploy scripts were targeting the legacy
privilegedescalation-dev namespace, which is not managed by Flux GitOps
in privilegedescalation/infra.

The infra repo (PR #11) already provisions the headlamp-dev namespace
and corresponding RBAC (e2e-ci-runner-headlamp-rbac.yaml) that grants
the ARC runner SA (runners-privilegedescalation-gha-rs-no-permission in
arc-runners) the permissions needed to deploy/teardown the E2E
Headlamp instance.

This change aligns all E2E infrastructure to use headlamp-dev:
- .github/workflows/e2e.yaml: E2E_NAMESPACE=headlamp-dev
- scripts/deploy-e2e-headlamp.sh: default namespace and comments
- scripts/teardown-e2e-headlamp.sh: default namespace
- deployment/e2e-ci-runner-rbac.yaml: namespace and add missing events
  permission (already present in infra copy)

Refs: PRI-423

Co-authored-by: Chris Farhood <chris@farhood.org>
Co-authored-by: Paperclip <noreply@paperclip.ing>

.github/workflows/e2e.yaml

@@ -11,15 +11,15 @@ permissions:
   contents: read
 
 # Only one E2E run at a time: the shared E2E_RELEASE (headlamp-e2e) in
-# privilegedescalation-dev cannot be shared across concurrent runs.
+# headlamp-dev cannot be shared across concurrent runs.
 # cancel-in-progress: false (queue, don't cancel) — cancelling in-flight
-# runs may skip the if: always() teardown, leaving dangling cluster resources.
+# runs may skip the if:always() teardown, leaving dangling cluster resources.
 concurrency:
   group: e2e-${{ github.repository }}
   cancel-in-progress: false
 
 env:
-  E2E_NAMESPACE: privilegedescalation-dev
+  E2E_NAMESPACE: headlamp-dev
   E2E_RELEASE: headlamp-e2e
   # Pin to a known-good Headlamp version. Using :latest is risky because
   # the tag can change between CI runs, causing flaky failures when a newer