Add transmission dashboard to grafana

- Add node_exporter ansible role to enable textfile collector
- Add transmission_metrics role with script and LaunchAgent
  - Collects metrics every 60s via transmission RPC
  - Writes to /opt/homebrew/var/node_exporter/textfile/transmission.prom
- Update grafana role to provision dashboards from files
- Add transmission.json dashboard with:
  - Status indicator, torrent counts
  - Transfer speeds, cumulative stats
  - Time series graphs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude/settings.local.json

@@ -2,7 +2,9 @@
   "permissions": {
     "allow": [
       "Bash(mcquack --help:*)",
-      "Bash(tea help:*)"
+      "Bash(tea help:*)",
+      "Bash(git add:*)",
+      "Bash(git commit:*)"
     ]
   }
 }