feat: add next/link mock with useLinkStatus

[yatishgoel]

Summary

Adds a Storybook-friendly mock for next/link, including the useLinkStatus hook introduced in Next 15.3. Previously, @storybook/nextjs-vite had no Link mock at all — stories using next/link (and especially useLinkStatus) would fail with:

TypeError: (0 , next_link__WEBPACK_IMPORTED_MODULE_2__.useLinkStatus) is not a function

What changed

• New alias module at src/plugins/next-mocks/alias/link/index.tsx — a Storybook-friendly Link mock (records click actions via fn()) plus a mockable useLinkStatus hook that defaults to { pending: false }.
• Registered aliases in src/plugins/next-mocks/plugin.ts for:
  • next/link
  • @storybook/nextjs/link.mock
  • @storybook/nextjs-vite/link.mock
  • @storybook/experimental-nextjs-vite/link.mock
• Build entry added in tsup.config.ts.
• Package exports added for ./browser/mocks/link and ./node/mocks/link in package.json.

This mirrors how navigation, router, headers, and cache are wired today.

Context

Companion PRs in the main Storybook repo:

• Next.js: Add useLinkStatus mock to next/link export mock storybook#34593 — original useLinkStatus fix for @storybook/nextjs by @philwolstenholme
• Next.js Vite: Add Link mock with useLinkStatus to nextjs-vite framework storybook#34736 — my matching changes in @storybook/nextjs-vite

@valentinpalkovic asked me to bring the LinkMock over here since the equivalent didn't exist for nextjs-vite. See the conversation on #34593 for context.

Test plan

• pnpm build succeeds and emits:
  • dist/plugins/next-mocks/alias/link/index.js
  • dist/plugins/next-mocks/alias/link/index.cjs
  • dist/plugins/next-mocks/alias/link/index.d.ts
  • dist/plugins/next-mocks/alias/link/index.d.cts
• pnpm check (biome) passes clean
• Manually verify in a Storybook sandbox that a story importing useLinkStatus from next/link no longer throws and that useLinkStatus can be overridden via parameters.nextjs.navigation / mock module to return { pending: true }.