Port Mosquitto and ntfy to ringtail k3s, retire Apple Silicon Detector (#216)

## Summary
- Delete `ansible/roles/frigate_detector/` and remove from indri playbook — the Apple Silicon Detector is retired
- Move Mosquitto (MQTT) ArgoCD app from indri minikube to ringtail k3s
- Move ntfy ArgoCD app from indri minikube to ringtail k3s
- Update Frigate docs to reflect detector removal and planned RTX 4080 migration
- Manifests are reused as-is (same `argocd/manifests/mosquitto/` and `argocd/manifests/ntfy/`), just pointed at ringtail

## Deployment

After merge:
1. Sync indri ArgoCD `apps` app with prune to remove old mosquitto/ntfy apps:
   ```
   argocd app sync apps --prune
   ```
2. Sync new ringtail apps:
   ```
   argocd app sync mosquitto-ringtail
   argocd app sync ntfy-ringtail
   ```
3. Manually clean up the detector LaunchAgent on indri:
   ```
   ssh indri 'launchctl unload ~/Library/LaunchAgents/mcquack.eblume.frigate-detector.plist'
   ssh indri 'rm ~/Library/LaunchAgents/mcquack.eblume.frigate-detector.plist'
   ```

## Notes
- Frigate on indri will lose MQTT/ntfy connectivity — this is expected (user confirmed no downtime concerns)
- ntfy Tailscale Ingress hostname `ntfy` will transfer from indri ProxyGroup to ringtail ProxyGroup
- Caddy on indri proxies `ntfy.ops.eblu.me` → `ntfy.tail8d86e.ts.net`, so no Caddy changes needed
- Frigate + frigate-notify will be ported to ringtail in a follow-up PR

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: https://forge.ops.eblu.me/eblume/blumeops/pulls/216

ansible/playbooks/indri.yml

@@ -175,5 +175,3 @@
       tags: jellyfin_metrics
     - role: caddy
       tags: caddy
-    - role: frigate_detector
-      tags: frigate_detector