Add raft/health Prometheus metrics (rebased #105)

[renecannao]

Summary

Rebased and lightly polished community PR #105 onto current master.

• Health/ready/raft/discovery/recovery Prometheus metrics from @rfpronk
• orchestrator_health_is_live now reflects recent health-check ticks (not always 1)
• Help text notes raft gauges are 0 when raft is disabled
• Comment on metrics-tick GetReplicationAnalysis cost

Closes / supersedes landing path for #105 once CI is green.

Test plan

• go test ./go/metrics/
• go build ./go/cmd/orchestrator
• CI full suite

[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

[coderabbitai]

Warning

Review limit reached

@renecannao, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 12 minutes

Enable usage-based reviews in Billing to review now. Otherwise, wait until the next included review is available.
You're only billed for reviews past your plan's rate limits ($0.25/file).

How can I continue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

To avoid repeated limits, reduce automatic review volume by pausing incremental auto-reviews earlier, using label-based review opt-in, excluding WIP or generated PR titles, or requesting reviews manually when the PR is ready. If your team needs uninterrupted high-volume reviews, an organization admin can enable usage-based reviews.

How do review limits work?

CodeRabbit enforces per-developer PR review limits for each organization. Most developers receive the normal plan review availability.

For paid Pro and Pro+ PR reviews, CodeRabbit uses adaptive limits for sustained high-volume activity. When a developer's recent PR review activity reaches the 95th percentile or higher among CodeRabbit users, additional reviews become available more gradually as earlier reviews age out of the rolling window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 234a1fc3-640f-48ba-bd37-2244c471e875

📥 Commits

Reviewing files that changed from the base of the PR and between 0bc318c and b9ca570.

📒 Files selected for processing (3)

• go/logic/orchestrator.go
• go/logic/topology_recovery.go
• go/metrics/prometheus.go

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/pr105-metrics-rebase

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}