internal: scope tend workflow-update Notable changes to consumer-relevant entries

[prql-bot]

Codifies maintainer feedback that would otherwise have been lost.

What happened

On #5986 (the 0.1.3 → 0.1.4 tend workflow update), @max-sixty flagged that the PR's Notable changes list included a tend-internal entry — "Publish GitHub Releases from CHANGELOG.md on tag push" — that doesn't affect how tend behaves in this repo (comment):

these should only list the changes relevant to consuming repos, not the internal changes to tend

The bot (run 27427152797) acknowledged the feedback but recorded it only to its file-based memory under /home/runner/.claude/.../memory/. CI runners are fresh each run, so that directory does not persist — the guidance would have evaporated before the next nightly regenerates the tend/update-workflows PR. Per the bundled running-in-ci Learning from Feedback guidance, generalizable maintainer feedback should be codified in this repo's running-tend overlay, not in (ephemeral) memory.

The fix

Adds a short tend workflow-update PRs section to .claude/skills/running-tend/SKILL.md recording the scoping rule, so future nightly runs apply it when composing the Notable-changes list.

Gate assessment

• Confidence: explicit maintainer feedback; generalizable to all future workflow-update PRs. The failure mode is invisible — the lost-to-ephemeral-memory guidance would not resurface as a CI failure.
• Magnitude: small, targeted rule codifying an explicit maintainer instruction (not invented guidance).

Found during the daily review-runs sweep.