[LaPaGaYo]

Summary

• Add worker-side GitHub App installation token minting with per-installation in-memory caching.
• Wire GitHub REST reconciliation through a target-scoped token provider while preserving static token fallbacks for local development.
• Document local PAT fallback and production-style GitHub App worker credentials.

Test Plan

• npm test --workspace @the-platform/worker
• npm run lint --workspace @the-platform/worker
• npm run typecheck --workspace @the-platform/worker
• npm test
• npm run lint
• npm run typecheck
• npm run build

Scope Notes

• This PR does not include GitHub App installation/authorization UI. That remains the next product slice.