Fix GitHub numeric issue resolution

[miyaontherelay]

Summary

• resolve numeric GitHub issues through deterministic compact and nested repository paths before using repo-scoped fallback listings
• preserve multi-repository ambiguity while surfacing provider failures and source-aware resolution errors
• infer GitHub issueSource for org-routed configs without Linear signals and preserve explicit or legacy Linear behavior
• cover Relayfile listTree cursor pagination without changing the existing MountClient pagination contract

Validation

• focused issue dispatch <number> can't resolve GitHub issues: resolver reads one page of listTree; issueSource auto-detect silently picks Linear #81 and Improve local clone path resolution #80 integration suite: 118/118 passed
• full npm test: 38 files, 751/751 passed
• npm run build
• npm pack --dry-run: 258 files
• git diff --check
• independent shadow review: approved with no blockers

PR #80 is integrated at base af1499b; its async local config resolution and checkout preflight behavior remain intact.

Fixes #81

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!