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>

docs/PACKAGE-FORMAT.md

@@ -1,6 +1,6 @@
 # Package Format
 
-Switchboard packages are distributed as `.pkg` files -- ZIP archives with a standard internal structure.
+Armature packages are distributed as `.pkg` files -- ZIP archives with a standard internal structure.
 
 ## ZIP Structure
 
@@ -125,6 +125,6 @@ To bundle custom packages into a Docker image:
 
 1. Place your package in `packages/your-package/` with a `manifest.json`.
 2. Run `cd packages && bash build.sh all`.
-3. Build the image: `docker build -t my-switchboard .`
+3. Build the image: `docker build -t my-armature .`
 
 The Dockerfile builds all packages and copies them into the bundled packages directory.