feat: add wiki-link hover cards

[maccman]

Why

Hosts need a supported way to attach local preview content to rendered wiki links without reaching into Meowdown DOM internals. The hover lifecycle also has to survive editor transactions so deleting or rewriting the hovered mark always closes the overlay.

What changed

• add a delegated, transaction-aware wiki-link hover handler with direct visible-element anchors
• add a passive WikilinkHoverCard with a 300 ms dwell, immediate leave, collision avoidance, focus neutrality, and request-scoped dismissal
• add interactive and renderEmbeds controls to MarkdownView for inert local preview rendering
• resolve wiki-link clicks and hovers from the hidden source holder, fixing adjacent wide-alias hit testing
• document the public core and React APIs and cover link deletion, replacement, teardown, rerenders, collisions, and passive rendering

Testing

• pnpm typecheck
• pnpm lint
• pnpm build
• CI=1 MEOWDOWN_TEST_BROWSER=chromium pnpm exec vitest run — 90 files, 1,681 passing tests and 13 expected failures
• targeted WebKit feature suite — 43 tests passed

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[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/prosekit/meowdown/@meowdown/core@288

npm i https://pkg.pr.new/prosekit/meowdown/@meowdown/react@288

commit: 834b053

[ocavue]

I will simplify it in another PR

[ocavue]

implemented in #291