Merge prgs/master into feat/issue-389-review-workflow-load-proof and
preserve workflow-load gates while adopting master test harness patterns
(_seed_ready_review_decision, reviewer leases, expected_head_sha).
Add gitea_load_review_workflow and in-process session proof required before
gitea_submit_pr_review, gitea_mark_final_review_decision, and gitea_merge_pr.
Capability and runtime context report workflow-load status; stale or missing
proof fails closed with recovery handoff text that forbids approve/merge replay.
sysadmin