[PR Genius] Add statistics dashboard: success rate, latency, PR type distribution

[Ikalus1988]

Goal

Add a statistics dashboard for PR Genius workflow metrics.

Context

PR Genius has 282 runs with excellent recent performance (96/100 success in last 100 runs). But there's no dashboard to track:

• Success/failure/skip rates over time
• Latency distribution (median ~13s)
• PR type distribution (code, docs, mixed)
• Human adoption rate (did the maintainer follow the advice?)

Scope

• Create scripts/pr_genius_stats.py that:
  • Fetches workflow runs from GitHub API
  • Computes: success rate, failure rate, skip rate, median/p95 latency
  • Breaks down by time window (last 7d, 30d, all-time)
  • Exports to data/pr-genius-stats.json
• Add GET /api/insights/pr-genius endpoint to Worker
• Create docs/insights/pr-genius.html dashboard page
• Update workers/README.md with new endpoint

Deliverable

• Stats script runs and outputs JSON
• Dashboard page shows metrics
• API endpoint serves stats

Labels

ready, agent-friendly, zero-bounty

---

This repo is using Opire - what does it mean? 👇

💵 Everyone can add rewards for this issue commenting /reward 100 (replace 100 with the amount).
🕵️‍♂️ If someone starts working on this issue to earn the rewards, they can comment /try to let everyone know!
🙌 And when they open the PR, they can comment /claim #1035 either in the PR description or in a PR's comment.

🪙 Also, everyone can tip any user commenting /tip 20 @Ikalus1988 (replace 20 with the amount, and @Ikalus1988 with the user to tip).

📖 If you want to learn more, check out our documentation.