Bumps version to 0.2.0 (root + apps/web package.json) and adds
CHANGELOG.md as the canonical human-readable history, mirrored by
apps/web/lib/changelog.ts as the in-app data source (single
ChangelogList component renders both).
- /changelog: user-facing page, linked from the account dropdown.
- /admin/changelog: same list, plus a "Version" card on the admin
overview dashboard linking to it.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>