## Overview
This PR addresses a significant growth in the repository's open issues (2342) and PRs (440) by optimizing the automated stale policy and adding visibility into backlog health.
## Changes
1. **New Metrics**:
- `backlog_health.ts`: Tracks the median age (in days) of the 100 oldest open PRs and issues. This provides a "worst-case" signal for backlog stagnation.
- `stale_ratio.ts`: Tracks the percentage of open items currently labeled as `stale`.
2. **Stale Policy Optimization**:
- Increased `operations-per-run` in `.github/workflows/stale.yml` from default (~30) to 500 total (300 for issues, 200 for PRs).
- Split the stale job into two parallel jobs (`stale-issues` and `stale-prs`) to increase daily throughput and prevent issues from blocking PR processing.
## Rationale
Metrics analysis showed that while the repository has excellent "Fast Path" performance (PRs merged in ~23 hours), it has a massive "Slow Path" backlog that is likely not being touched by automation due to default throttling in `actions/stale`. By increasing the processing limit, we can accelerate the cleanup of stale items and help maintainers focus on active work.
## Impact
- **Productivity**: Reduces "noise" in the issue tracker and PR list.
- **Observability**: New metrics will allow the "Bot Brain" to monitor the effectiveness of these policy changes over time.
- **Latency**: Expected to decrease the median age of open items as stale ones are closed.
gemini-cli[bot]