fix: /check-golf --measure crash (def_body_changed -> def_value_changed)

[Vilin97]

The measure-path file selection in scripts/check_golf.py (added in #1356) references a nonexistent FileReport attribute def_body_changed; the field is named def_value_changed. As a result every /check-golf run since #1356 crashes with an AttributeError after building the head, so the report comment is never posted/updated (see e.g. this run on #1364).

One-line fix.

🤖 Generated with Claude Code

[github-actions]

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[jstoobysmith]

Approved - will merge now