Push tag embed-v0.6.0 and create its GitHub release

[hhkaos]

Context

apps/embed was bumped to 0.6.0 and merged to main in c8d48e7 (on top of 716ab2d), but the release-tag step of the checklist in apps/embed/CLAUDE.md couldn't be completed from that session: git push origin embed-v0.6.0 returned a 403 from GitHub (not a network/proxy issue — the proxy's own failure log was empty), and that session's GitHub tools only expose read access to releases/tags (list_releases, get_release_by_tag, list_tags, get_tag), not write access. The commits themselves are already on main; only the tag + release object are missing.

This means tools.opentechevents.org is already serving the 0.6.0 build (the deploy workflow runs on every push to main), but the versioned snapshot apps/embed/versions/v0.6.0/, the playground's version table row, and the changelog all point to a release/tag that doesn't exist on GitHub yet — anyone trying to pin embed-v0.6.0 right now gets a 404, the exact failure mode apps/embed/CLAUDE.md warns about ("a version bump in package.json is not a release").

What's already done (on main, commit c8d48e7)

• Bug fix: rawLocationText() in apps/embed/src/render.ts no longer shows an "Online" location label for an event with no attendanceMode declared at all — it now falls back to "Venue not specified", same as an in-person event with no venue. Regression test added in apps/embed/test/element.test.ts.
• apps/embed/package.json bumped 0.5.0 → 0.6.0 (minor — also releases the already-queued playground restructure #53 and <ote-subscribe layout="badges"> redesign that were sitting under "Unreleased").
• apps/embed/CHANGELOG.md updated with the 0.6.0 section.
• apps/embed/versions/v0.6.0/ snapshot committed (node build.mjs --snapshot-version output).
• apps/embed/index.html's playground version table updated with a static v0.5.0 row (it was missing — v0.5.0 had been released without ever getting one) plus the templated current-version row now reading v0.6.0.

What's left — needs someone with full push access

1. From a checkout with push access to tags:

   git fetch origin main
   git tag -a embed-v0.6.0 c8d48e7 -m "embed v0.6.0"
   git push origin embed-v0.6.0

2. Create the GitHub release from that tag (Releases → Draft a new release → choose embed-v0.6.0). Suggested body:

   ### Fixed
   - An event with no `attendanceMode` declared and no `location` no longer shows an "Online" label — falls back to "Venue not specified".
   
   ### Changed
   - Playground restructured into tabs with collapsible control sections (#53).
   - `<ote-subscribe layout="badges">` triggers redesigned as colored-pill icon+text badges.

3. Sanity-check afterwards: git ls-remote --tags origin | grep embed-v0.6.0 should print something, and https://tools.opentechevents.org/embed/v0.6.0/ote-events.js should resolve — both per the verification step apps/embed/CLAUDE.md already documents for this exact failure mode.