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-nginx.conf

@@ -3,10 +3,10 @@ events {
 }
 
 http {
-  upstream switchboard {
-    server switchboard-1:80;
-    server switchboard-2:80;
-    server switchboard-3:80;
+  upstream armature {
+    server armature-1:80;
+    server armature-2:80;
+    server armature-3:80;
   }
 
   # WebSocket upgrade map
@@ -19,7 +19,7 @@ http {
     listen 80;
 
     location / {
-      proxy_pass http://switchboard;
+      proxy_pass http://armature;
       proxy_set_header Host $host;
       proxy_set_header X-Real-IP $remote_addr;
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
@@ -28,7 +28,7 @@ http {
 
     # WebSocket endpoint
     location /ws {
-      proxy_pass http://switchboard;
+      proxy_pass http://armature;
       proxy_http_version 1.1;
       proxy_set_header Upgrade $http_upgrade;
       proxy_set_header Connection $connection_upgrade;