#### Brief overview of PR changes/additions
- `add-milestone` resolves the milestone by exact title first and then
by version prefix, so `5.0.0` finds `5.0.0 next release` again, and
fails loudly instead of assigning nothing. 191 PRs merged since 4.22.0
have no milestone.
- `TKeySequenceEditTest`'s two focus traversal cases no longer fail
under a bare Xvfb: ctest pins the offscreen platform on X11, and a
direct run without a window manager skips with a message instead of
burning the activation timeout twice.
#### Motivation for adding to Mudlet
Both were failing silently. The milestone step matched a title that no
longer exists and exited 0; and the traversal tests were the one red
mark in an otherwise green local suite, which everybody had to re-derive
as environmental.
The milestone lookup is now a script under `.github/scripts/`, covered
by a new `MilestoneResolutionTest` that runs it against a stubbed `gh`.
Re-introducing the original bug makes that test fail.
Worth knowing: `add-milestone` on this PR still assigned nothing,
because `pull_request_target` runs the copy of the workflow that is on
the base branch. It takes effect for pull requests opened after this
merges.
#### Other info (issues closed, discussion etc)
- Closes#9671 - CI: add-milestone silently assigns nothing - metadata
says "4.23.0" but the milestone is titled "4.23.0 next release"
- Closes#9575 - TKeySequenceEditTest: two traversal tests fail under
bare Xvfb (no window manager)
Test case: `ctest -R 'MilestoneResolutionTest|TKeySequenceEditTest'`,
plus `xvfb-run --auto-servernum ctest -R TKeySequenceEditTest` for the
case #9575 is about.
Assisted-by: Claude:claude-opus-5
