feat(a11y): keyboard-accessible task glance tooltip

[tink-bot]

Task glance card (TaskGlanceTooltip) was mouse-only: mouseenter/mouseleave handlers, no focus path, no Escape, no aria-describedby. Keyboard and AT users got none of the glance info. Follow-up from #3544 review (flagged by the a11y pass there).

Now: opens on focus of the wrapped link (same delay), sets aria-describedby on the focused element while visible, Escape dismisses without moving focus (stops propagation + preventDefault only when it actually closed the tooltip, so a surrounding <dialog> stays open), hover behaviour unchanged. Teleport no longer gated on the hover media query — the canHover check moved into the mouse handler, so keyboard focus works on touch devices too. Still not hoverable (pointer-events: none) — out of scope.

How to verify

1. Open a project in the List view (task titles are wrapped in the glance tooltip).
2. Tab until a task title link has focus and wait about a second.
3. Expected: the glance card appears above the link; the focused link carries aria-describedby pointing at the card's id.
4. Press Escape.
5. Expected: the card disappears, focus stays on the link, no other Escape handler fires (nothing else closes).
6. Tab to the next task title.
7. Expected: the previous card is gone and a new one appears for the focused task.
8. Hover a title with the mouse.
9. Expected: unchanged — card shows after the delay and hides on mouse leave.
   Before this PR: focusing a title showed nothing; only hover worked.

[github-actions]

Preview Deployment

Preview deployments for this PR are available at:

URL	Tag	Commit
https://pr-3566.preview.vikunja.dev	ghcr.io/go-vikunja/vikunja:pr-3566	latest
https://sha-a4f092fa50ad6910b7423e148701db64d7796fb5.preview.vikunja.dev	ghcr.io/go-vikunja/vikunja:sha-a4f092fa50ad6910b7423e148701db64d7796fb5	a4f092f

The preview environment will start automatically on first visit. Subsequent pushes to this PR will update the pr-3566 image — the preview picks up the new version on restart. The per-commit URLs point to a specific version and will not change.

Run locally with Docker

docker pull ghcr.io/go-vikunja/vikunja:pr-3566
docker run -p 3456:3456 ghcr.io/go-vikunja/vikunja:pr-3566

Last updated for commit a4f092f