tune — turn friction into fixes

The issue-to-pr pipeline no longer has an always-on "improve this skill" step. Instead each run appends one line to .claude/issue-to-pr/friction.log (repo-local, gitignored) whenever a step genuinely fought back — a stop that should not have happened, an unclear instruction, a missed detection, a script that surprised the model. This skill batches that evidence into real changes.

Steps