New reusable library with clean function boundaries for the PR lifecycle:
- pr_create, pr_find_by_branch — PR creation and lookup
- pr_poll_ci — poll CI with infra vs code failure classification
- pr_poll_review — poll for review verdict (bot comments + formal reviews)
- pr_merge, pr_is_merged — merge with 405 handling and race detection
- pr_walk_to_merge — full orchestration loop (CI → review → merge)
- build_phase_protocol_prompt — git push instructions for agent prompts
The pr_walk_to_merge function uses agent_run() which callers must define
(guarded stub provided). This bridges to the synchronous SDK architecture
where the orchestrator bash loop IS the state machine — no phase files.
Extracted from: dev/phase-handler.sh, dev/dev-poll.sh, lib/ci-helpers.sh
Smoke test updated to include the new library.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>