Add update_head_reference.sh: automate the head_reference checkpoint ritual, so it actually happens instead of being forgotten.

2026-08-30T06:13:53Z

Refreshing head_reference/ (rebuild release binary, sd10+sn5m sweep across all three curated suites, copy logs, tag the commit, archive the binary) was, until now, a several-minute manual dance repeated by hand every time a commit became the new comparison baseline -- exactly the kind of multi-step ritual an AI assistant with no persistent memory across sessions will reliably forget to fully repeat. Scripted the mechanical parts: build, 6-way sweep, log copy, git tag (head- reference-, the durable/versioned source of truth for "which commit was checkpoint N" -- see head_reference/README.md's new "Checkpoint history convention" section), and binary archive (a rebuild-avoidance cache alongside the tag, not a replacement for it). Does NOT write the README's prose sections (what changed, why, how to read the net score) -- that still needs a human/Claude actually looking at the diff and the numbers this script prints at the end, not a template trying to guess at them. Checks for a dirty working tree and warns rather than silently tagging something that doesn't correspond to a real commit -- the intended sequence is still git commit first, then this script, same as precommit_check.sh's gate runs before a commit rather than replacing it. precommit_check.sh: two lines printing the actual next-step commands ("git commit", "./update_head_reference.sh") after a passing check, so the two scripts' relationship is visible right where the first one succeeds. Co-Authored-By: Claude Sonnet 5 Claude-Session: https://claude.ai/code/session_01M9ZDiJhiUajUxh95mTXCFJ

typhoon.git/src/update_head_reference.sh, branch master

Add update_head_reference.sh: automate the head_reference checkpoint ritual, so it actually happens instead of being forgotten.