v2.9.9 (2026-09-07)

Debugging micro-discipline: minimise, tag, and seam

• systematic-debugging: shrink the repro until every remaining element is load-bearing (removing any one of them clears the failure); the minimised repro becomes the regression test.
• systematic-debugging closeout: tag temporary debug logs with a unique prefix (e.g. [DEBUG-a4f2]) during diagnosis so cleanup is one grep, and confirm their removal before close.
• verification-before-completion: place the regression test at the seam that exercises the real bug pattern as it occurs at the call site; a seam too shallow to replicate the triggering chain gives false confidence. If no such seam exists, record the missing seam as the finding (the architecture prevents locking the bug down) and lower confidence. No new owner, file, or ceremony.

Verification boundary

• Version-bump audit passed: 8 declared manifests in sync at 2.9.9; no undeclared references.
• tests/e2e/workflow-quality-check.sh passed; git diff --check passed.