Add Forgejo repository health metrics and Grafana dashboard (#245)
## Summary
- New `forgejo_metrics` Ansible role that queries the Forgejo REST API every 60s and writes Prometheus textfile metrics (open PRs, issues, languages, releases, commits, Actions runs/duration/success)
- Grafana dashboard "Forgejo Repository Health" with 12 panels across 4 rows: overview stats, CI/CD health, repository info, and staleness tracking
- Deletes superseded `forgejo-actions-dashboard` plan doc (this implementation covers a broader scope)
## Deployment and Testing
- [ ] `mise run provision-indri -- --tags forgejo_metrics` to deploy the collector
- [ ] `ssh indri 'cat /opt/homebrew/var/node_exporter/textfile/forgejo.prom'` to verify metrics
- [ ] `argocd app sync grafana-config` to deploy the dashboard
- [ ] Check Grafana dashboard "Forgejo Repository Health" loads with data
- [ ] `mise run services-check` passes
Reviewed-on: https://forge.ops.eblu.me/eblume/blumeops/pulls/245
Erich Blume
2c081eed28