fix(ci): add CHARON_EMERGENCY_TOKEN to E2E test workflows

Add missing emergency token environment variable to all E2E test workflows to
fix security teardown failures in CI. Without this token, the emergency reset
endpoint returns 501 "not configured", causing test teardown to fail and
leaving ACL enabled, which blocks 83 subsequent tests.

Changes:

Add CHARON_EMERGENCY_TOKEN to docker-build.yml test-image job
Add CHARON_EMERGENCY_TOKEN to e2e-tests.yml e2e-tests job
Add CHARON_EMERGENCY_TOKEN to playwright.yml playwright job
Verified:

Docker build strategy already optimal (build once, push to both GHCR + Docker Hub)
Testing strategy correct (test once by digest, validates both registries)
All workflows now have environment parity with local development setup
Requires GitHub repository secret:

Name: CHARON_EMERGENCY_TOKEN
Value: 64-char hex token (e.g., from openssl rand -hex 32)
Related:

Emergency endpoint rate limiting removal (proper fix)
Local emergency token configuration (.env, docker-compose.local.yml)
Security test suite teardown mechanism
Refs #550

.github/workflows/docker-build.yml

@@ -467,6 +467,9 @@ jobs:
     needs: build-and-push
     runs-on: ubuntu-latest
     if: needs.build-and-push.outputs.skip_build != 'true' && github.event_name != 'pull_request'
+    env:
+      # Required for security teardown in integration tests
+      CHARON_EMERGENCY_TOKEN: ${{ secrets.CHARON_EMERGENCY_TOKEN }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6