feat: category-aware default fallbacks

[onmax]

Fixes #544

Automatic font fallback selection based on font categories (serif, sans-serif, monospace). Maintains full backward compatibility.

Changes

• Auto-selects appropriate fallbacks based on font category
• Added categoryFallbacks option for customization
• Extended FontFaceMetrics with optional category field

[netlify]

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[pkg-pr-new]

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npm i https://pkg.pr.new/fontaine@674

npm i https://pkg.pr.new/fontless@674

commit: 985453b

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 53.08%. Comparing base (d66809d) to head (985453b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #674      +/-   ##
==========================================
- Coverage   53.40%   53.08%   -0.32%     
==========================================
  Files          11       11              
  Lines         734      729       -5     
  Branches       93       93              
==========================================
- Hits          392      387       -5     
  Misses        342      342              

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[danielroe]

I think we do something similar in fontless. maybe we could export the shared/overlapping utils or defaults from fontaine so we could share?

[onmax]

I think we do something similar in fontless. maybe we could export the shared/overlapping utils or defaults from fontaine so we could share?

Refactored!