feat: GitHub issue scraper for auto-posting bounties (#840)

[wingo-blue]

Summary

A backend service that automatically scrapes GitHub issues from configured repositories and posts them as SolFoundry bounties with appropriate reward tiers.

Features

Scanner (Python CLI)

• Scan configured repos via GitHub Search API
• Auto-classify issues into T1/T2/T3 tiers
• Estimate potential rewards based on labels and content
• Deduplication to avoid reposting
• Dry-run mode for preview

Webhook Server

• Real-time issue detection via GitHub webhooks
• HMAC-SHA256 signature verification
• Auto-posts newly opened issues to SolFoundry

TypeScript Automaton Service

• Integrates with the SolFoundry automaton system
• Same scanning logic, TypeScript-native
• Ready for scheduled execution

Files

\
scripts/github-scraper.py # Main Python scanner + webhook server
scripts/test_github_scraper.py # 14 unit tests
scripts/github-scraper-config.yaml # Configuration template
automaton/scrapers/github-issue-scraper.ts # TypeScript automaton service
\\

Default Scan Targets

Repo	Description
claude-builders-bounty	Claude Code builder bounties (-)
warpspeedopen-source/warpspeed-bounties	React Native bounties (-)
PlatformNetwork/bounty-challenge	CLI bug bounties (24K+ issues)
SecureBananaLabs/bug-bounty	Web security bug bounties (+)

Closes #840

Wallet: A6YMFucCab3KvqLxHAtaUFxFUReSTPUg4dTxn1kQy7t