[yangshun]

What this fixes

• Vue could prefetch the same page twice. Moving the pointer out of a hover-prefetch Link and back in before the delay fired started a second timer without clearing the first, so both fired. Vue now clears the pending timer first, like the other adapters.
• Svelte rejected readonly prefetch arrays. <Link prefetch={['hover', 'visible'] as const}> was a type error in Svelte only, because its props took a mutable Array. Svelte now accepts ReadonlyArray like React, Vue and Solid.
• The four Link copies can't drift apart again. The props, strategy and method types, and the prefetch, click and visibility logic each live in one place. Vue's runtime prop declarations are now type-checked against the shared BaseLinkProps, so a mismatch fails vp run check.

Summary

Each framework adapter had its own copy of the Link props, the prefetch strategy and method unions, and roughly 150 lines of prefetch, click and visibility logic. This PR moves them into void/pages-client, next to the shared <Form> helpers from form-presentation.ts:

• Types: BaseLinkProps, LinkPrefetchStrategy, LinkNavigateEvent, ResolvedLink. They reuse the existing NavigationMethod and CacheForInput types instead of new copies.
• Helpers:
  • resolveLink: works out the method and destination, and throws the two "GET only" errors
  • linkPrefetchStrategies
  • prefetchLink
  • handleLinkClick: the click checks, then onNavigate, then visit
  • observeLinkVisible

Each adapter keeps only what differs by framework: reactivity, event-name casing, calling the user's own handlers (Vue handler arrays, Solid [fn, data] pairs), merging style, and rendering. The four adapter Link files are 466 lines shorter in total.

⚠️ Drift between the copies

The four copies had already diverged. This PR picks one behavior for each difference:

Drift	Before	After
prefetch array type	Svelte accepted only a mutable Array, so prefetch={['hover', 'visible'] as const} was a type error in Svelte only	Every adapter accepts ReadonlyArray
Re-hover before the delay fires	Vue started a new hover timer without clearing the pending one, so a quick leave and re-enter could prefetch twice	Vue clears the pending timer first, like React, Svelte and Solid
Prefetch options	React and Solid declared their own PrefetchOptions without method; Vue and Svelte used the engine type and passed method: 'GET'	Every adapter uses the engine type and omits method. It was always GET, which is the router's default
prefetch left undefined	Only Solid explicitly treated it as off; the others relied on a default value	resolveLink and linkPrefetchStrategies treat undefined as off

Everything else behaves as before: the same error messages, modified-click, download and cross-origin handling, onNavigate cancellation, GET data merging, and hover/click/mount/visible prefetching.

Not changed here: LinkProps is still exported publicly only from @void/solid. Exporting it from every adapter is a public API decision for a follow-up.

Test plan

• vp run check: all 33 projects pass, including Vue's runtime-props-vs-BaseLinkProps check
• vp lint and vp fmt
• New packages/void/test/unit/pages-link.test.ts: 22 tests for the shared helpers
• Adapter browser contract suites (React, Vue, Svelte, Solid), Link unit tests and route href type checks: 219 passed after rebuilding the playgrounds with vp run build:all
• Full vp test run: 15,547 passed. The one failure is plugin-cloudflare-v2.test.ts > "keeps Container builds deferred…", which hit the 5-second limit at 5.5 seconds under full-suite load and passes on its own in about 1.5 seconds. It doesn't touch Link.

Note for local testing: the adapter integration suites only build their playground when dist is missing. A stale playground/*-pages/dist makes them test old code, so run vp run build:all first.

🤖 Generated with Claude Code

[cpojer]

Nice cleanup. Definitely best to keep the client logic abstract and shared across all the frameworks.