fix: avoid retaining detached links during preloading

[svelte-triage-bot]

• Hold hovered and last-preloaded anchors weakly so links removed without mouseleave cannot retain detached page or dialog subtrees.
• Preserve #16325's reduced mouse-event traffic and 20 ms rest delay, and #15915's cache/navigation resets. Navigation-only cleanup was rejected because it misses in-place DOM removal.
• Keep href and priority deduplication from #15191 and #13530, but snapshot SVG href strings: retaining SVGAnimatedString still retains its anchor even when the element reference is weak.
• Cover HTML/SVG links with disabled, code, and data preloading, departed pages, and SVG href/priority transitions.

Fixes #17487

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 565bf04:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/565bf0406f3e0a045ff1823bba418d3502c009c8

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/17488

Note

This PR is from a fork. A maintainer must approve approve each commit before it can be built and installed.

[changeset-bot]

🦋 Changeset detected

Latest commit: 565bf04

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR