Agent Skills: pr-cycle

Automated PR review cycle for codesmith when PR mode applies. Opens the PR, waits for Gemini Code Assist review via the `await_pr_review` tool, dispatches `codesmith-validator` to assess each unresolved thread against the codebase, implements approved fixes via `codesmith-worker`, responds to threads, requests re-review, and loops until Gemini approves or a context-handoff signal fires. Escalates to human for the final merge decision. NEVER auto-merges. Used at V-phase PR-review gate (Lock 11 gate 5) when PR mode applies; pairs with `local-merge` for the non-PR alternative.