feat(fonts): fallback improvements

[florian-lefebvre]

Changes

• Improves the generated fallback name. It now takes names with quotes into account by removing the quotes to avoid creating invalid strings
• Refactors font face declaration generation so the logic is shared
• Improves the quality of fallbacks by pulling system metrics (RFC feedback):
  • I didn't notice that initially but to get better fallbacks, you need to provide the metrics of the target font file (done by reading the font file) as well as the metrics of the fallback font (system font eg. Arial)
  • So now, the metrics of system fonts used as fallbacks are put in a constant to avoid having to add the @capsizecss/metrics package (which is huge and was removed in fix(fonts): lighter fallbacks #13626)
• Makes changes to implementation copied from nuxt/fonts and capsize to simplify things

Testing

Tests added

Docs

Changesets

[changeset-bot]

🦋 Changeset detected

Latest commit: 16b1478

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

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[codspeed-hq]

CodSpeed Performance Report

Merging #13632 will not alter performance

_{Comparing fix/fonts-fallback-name (16b1478) with main (99af0d1)}

Summary

✅ 6 untouched benchmarks

[ematipico]

Looks good! I left nitpicks, but you can merge away :) One suggestion: let's put more description in the changeset, at least let's explain that these changes affect the experimental Fonts API.