ChangelogModal renders the repo-root CHANGELOG.md (bundled at build
time via Vite's ?raw query, 5 levels up from the component file) in
an overlay+panel modal. Markdown is parsed inline (`#`/`##`/`###`
headers, `-`/`*` lists, `**bold**`) with HTML-escape on every input
line — input is static repo content so the surface is closed.
Esc and overlay-click both call `onClose`. The keydown listener is
attached only while `open` is true via a $effect.
Three new Paraglide messages (en/es): `settings_about_view_changelog`,
`changelog_modal_title`, `changelog_modal_close`.
Unit tests (CHM-U-01..04) follow the Spinner.test.ts pattern (Svelte 5
mount/unmount + flushSync for the Escape spec).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
