rebrand: Switchboard Core → Armature

- Rename Go module switchboard-core → armature (155+ files)
- Rename Docker image → gobha/armature
- Rename K8s resources, secrets, deployments
- Rename Prometheus metrics switchboard_* → armature_*
- Rename env vars SWITCHBOARD_ADMIN_* → ARMATURE_ADMIN_*
- Rename DB names switchboard_core* → armature*
- Update all frontend branding, notification templates, docs
- Update CI scripts, e2e tests, Keycloak realm, nginx conf
- Rename scripts/switchboard-ca.sh → scripts/armature-ca.sh
- Rename k8s/switchboard.yaml → k8s/armature.yaml
- Rename chart alerting/dashboard files
- Fix: DockerHub push uses env: binding for secret injection
- Helm chart updated (name, labels, template functions, dashboard, alerting)
- Replace favicon/icon assets with Armature brand

No functional changes. Pure mechanical rename + CI fix.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ci/e2e-cluster-test.sh

@@ -103,7 +103,7 @@ done
 
 # ── Test 4: Stop one replica → stale sweep ────
 echo "=== Test 4: Stop node-3, wait for sweep ==="
-docker compose -f docker-compose-e2e.yml stop switchboard-3
+docker compose -f docker-compose-e2e.yml stop armature-3
 
 echo "  waiting ${STALE_WAIT}s for stale sweep..."
 sleep "$STALE_WAIT"
@@ -118,7 +118,7 @@ fi
 
 # ── Test 5: Restart replica → re-registers ────
 echo "=== Test 5: Restart node-3 ==="
-docker compose -f docker-compose-e2e.yml start switchboard-3
+docker compose -f docker-compose-e2e.yml start armature-3
 
 # Wait for startup + at least one heartbeat
 for i in $(seq 1 30); do