feat(fontless): expose preload fonts to server runtime

[hi-ogawa]

• Closes [fontless] support preload for ssr app #650
• Closes [fontless] Support SvelteKit #558

This PR exposes the list of font urls to be preloaded via virtual module fontless/runtime. This approach assumes the css file is transformed on server environment.

(Note that, until #655 lands, the preloaded font isn't the one actually used, so it's not effective yet.)

TODO

• test ssr framework
  • react router (see packages/fontless/examples/react-router-app)
  • rsc / waku chore: test fontless hi-ogawa/waku-nitro-example#1
  • astro https://github.com/hi-ogawa/reproductions/tree/main/fontless-astro
  • sveltekit https://github.com/hi-ogawa/reproductions/tree/main/fontless-sveltekit
    • the example is added as examples/sveltekit-app and removed svelte-app
  • tanstack start https://github.com/hi-ogawa/reproductions/tree/main/fontless-tanstack-start
  • qwik
    • qwik automatically add preload for all fonts by default, which is over-preloading. this should be disabled by qwikVite({ disableFontPreload: true })
  • analog
    • It uses transformIndexHtml, so no manual head setup is necessary.
  • nuxt https://github.com/hi-ogawa/reproductions/tree/main/fontless-nuxt
• docs
• discuss API

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[codecov]

Codecov Report

❌ Patch coverage is 3.48837% with 83 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.70%. Comparing base (d66809d) to head (d72f8e6).

Files with missing lines	Patch %	Lines
packages/fontless/src/vite.ts	2.38%	82 Missing ⚠️
packages/fontless/src/runtime.ts	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #651      +/-   ##
==========================================
- Coverage   53.40%   48.70%   -4.71%     
==========================================
  Files          11       12       +1     
  Lines         734      809      +75     
  Branches       93       94       +1     
==========================================
+ Hits          392      394       +2     
- Misses        342      415      +73     

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commit: d72f8e6