feat: issue proposer — auto-file GitHub issues from detection systems

[stackbilt-admin]

Summary

Port the issue proposer from the daemon (v1.62.1). Bridges detection systems to GitHub issues automatically.

What to port

• Module: issue-proposer.ts — 4 detectors, dedup via web_events, GitHub issue creation
• Registration in scheduled/index.ts

Detectors

1. Task failure patterns (repeated failure_kind)
2. Repo failure rates (>50% fail rate)
3. Scheduled task errors (>50% error rate in 24h)
4. RuntimeGuard correlations (high-score findings)
5. LLM trace anomalies (executor error rates)

Scrub checklist

• GitHub repo target should come from env config, not hardcoded
• Labels (self-improvement, bug) should be configurable

[stackbilt-admin]

🤖 AEGIS: Queued as task 1718ef19-db12-401f-a8c1-e1bf63c7a356 (proposed). Awaiting operator approval before execution.

[stackbilt-admin]

🤖 AEGIS: Queued as task f5a31c81-240c-494c-afc4-4b9065670b96 (proposed). Awaiting operator approval before execution.