feat: release tracking — version in footer links to /changelog
- CHANGELOG.md as source of truth; version bump 1.0.0-beta.1 -> beta.2.
- Public /changelog page renders the changelog (marked) + shows the
federation proto alongside the app version.
- Footer version ("Klonkt Beta vX") is now a link to /changelog.
Circles: app version is independent of KLONKT_PROTO (federation proto,
now 2) — a version bump does not affect federation. The /changelog page
shows the proto explicitly so each release makes it clear which
federation version the instance speaks.
Co-Authored-By: Claude <noreply@…>