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>

chart/templates/servicemonitor.yaml

@@ -2,16 +2,16 @@
 apiVersion: monitoring.coreos.com/v1
 kind: ServiceMonitor
 metadata:
-  name: {{ include "switchboard.fullname" . }}
+  name: {{ include "armature.fullname" . }}
   labels:
-    {{- include "switchboard.labels" . | nindent 4 }}
+    {{- include "armature.labels" . | nindent 4 }}
     {{- with .Values.monitoring.serviceMonitor.labels }}
     {{- toYaml . | nindent 4 }}
     {{- end }}
 spec:
   selector:
     matchLabels:
-      {{- include "switchboard.selectorLabels" . | nindent 6 }}
+      {{- include "armature.selectorLabels" . | nindent 6 }}
       app.kubernetes.io/component: backend
   endpoints:
     - port: http