feat(overlay): add in-app changelog modal

- Add a changelog modal opened from tray "View Changelog" or the update notification's "What's New" button; renders in-player or in its own window like the help modal
- Fetch changelog from the newest published release so newer-than-installed notes are visible, falling back to the bundled CHANGELOG.md on failure
- Group versions by minor line (current expanded, older folded), badge the installed version, tag newer ones "New"
- Support J/K/arrow navigation, Enter to fold/unfold, R to refetch, Esc to close
- Add changelog parsing/semver-compare utils and changelog IPC channel/runtime; bundle CHANGELOG.md into packaged builds
- Replace release/release-notes.md with changes/changelog-modal.md changeset entry

src/main/runtime/update/release-assets.test.ts

@@ -51,6 +51,13 @@ test('compareSemverLike orders prerelease identifiers within the same base versi
   assert.equal(compareSemverLike('0.15.0', '0.15.0-rc.1') > 0, true);
 });
 
+test('compareSemverLike ignores build metadata, which carries no precedence', () => {
+  assert.equal(compareSemverLike('0.15.0+build.2', '0.15.0+build.1'), 0);
+  assert.equal(compareSemverLike('0.15.0-rc.1+build.2', '0.15.0-rc.1+build.1'), 0);
+  assert.equal(compareSemverLike('0.15.1+build.1', '0.15.0+build.9') > 0, true);
+  assert.equal(compareSemverLike('0.15.0+build.1', '0.15.0-rc.1') > 0, true);
+});
+
 test('findReleaseAsset finds exact asset names only', () => {
   const release = {
     tag_name: 'v0.14.1',