A crew hold whose reason has not cleared in 24 h expires with a note that names the reason #6425

Flow work for #5930 (the steward's trap 2: holds outlive their reason). #6348 releases a red hold when the check turns green. This covers the hold whose reason never clears.

Done when:

• [ ] A hold the crew placed that is still standing 24 h after it was placed is released by the next tick, with a comment on the pull: "Hold expired after 24 h: <reason>. Back to <builder>." Then the pull goes back to its builder.
• [ ] A hold a person placed never expires.
• [ ] Tests: a 25 h crew hold is released with the note; a 23 h one stays; a person's hold stays.

Files: the hold module #6348 changes, and its test.

Replaced by #6918. The reviews found pull #6882 sound three times, except for one dead branch. #6918 says what done looks like now, including removing that branch, and starts from #6882's branch.