Record the Headbutt and Rock Smash commit in the session handoff

[no-card]

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/SESSION_HANDOFF.md

@@ -1088,3 +1088,9 @@ play so far: no open map has rocks, and Headbutt (the Ilex Forest tutor)
 and Rock Smash (a TM on Route 36) are not obtainable yet.
 
 Next: the remaining field items, MAIL and pack reordering (board #27).
+
+The increment was committed as `f259163` (`Closes #26`; the hook moved the
+card to Fait). Not pushed. Manual check: card #51 in "A tester" (the shake
+and tree battles against the original), with
+`test-saves/headbutt.crystal-save.json` from `tests/human-test-saves.test.ts`;
+importing it and headbutting was checked once in Chromium and WebKit.