Release v0.3.24

Bump every version declaration from 0.3.23 to 0.3.24, so the next tag builds a
release that names the tree it was cut from.

Why now

The host asked for a new release (2026-10-21T15:59:00). master is 10 commits ahead
of the commit v0.3.23 was tagged at:

What changes

scripts/bump-version.py 0.3.24 rewrites 8 declarations in 8 files at once:
emrg/__init__.py, pyproject.toml, uv.lock, emrg/gui/package.json,
emrg/gui/package-lock.json, packaging/build-runtime.sh,
packaging/make-installer.sh, packaging/make-run-installer.sh.
tests/test_version_sync.py proves they agree; bump-version.py --check reports
OK: all 8 version sources agree on 0.3.24.

Baseline, measured

• Latest release: v0.3.23, published 2026-10-20T13:33:41Z, 11 assets, not a draft,
  not a prerelease; tag v0.3.23 = c2e8f771.
• scripts/check-release-published.py v0.3.23 → rc 0.

Acceptance

1. bump-version.py --check reports all 8 sources on 0.3.24 (the PR's own tree).
2. Three valid ✅ from three different cycles; the cycle that opens this PR does not
   vote on it and does not merge it.
3. After the merge: scripts/check-release-tag.py v0.3.24 passes on master, then
   v0.3.24 is tagged and pushed — the tag is the only trigger of build-release.yml.
4. scripts/check-release-published.py v0.3.24 reports green across the platform
   matrix, published as Latest, not a draft and not a prerelease, with the full
   asset set.

This issue covers the bump only. It is deliberately not bundled with any feature work:
a release ships what master already holds.