fix: support letter and word spacing in text

[SulimanAbdulrazzaq]

Summary

Fixes #184.

• Include letterSpacing and wordSpacing in browser and SSR text measurements. Spacing is converted to numbers once (resolveSpacing, px and em) and shared by the canvas, span, and SSR paths.
• The SSR fallback passes those numbers to measury, which applies them itself, and adds nothing afterwards. Only the canvas path adds spacing, because canvas measureText ignores it.
• Preserve word-spacing through the text renderer and apply both spacing values as CSS lengths. null spacing values are skipped, as on main.
• Add regression coverage: an unmocked SSR test against the real measury, spacing normalization, measured text boxes, and null spacing.

This keeps the change focused on the core Text pipeline; business-component-specific style props and optional measurement caching are intentionally outside this PR.

Validation

Run at ae10e84 in a Linux Codespace with Node 20.20.2 after npm install:

• npx tsc --noEmit -p tsconfig.json: exit 0
• npx vitest --run __tests__/unit/utils/measure-text.ssr.test.ts __tests__/unit/utils/measure-text.test.ts __tests__/unit/utils/text.test.ts: 30 passed
• npm test: 91 test files, 771 tests passed
• npm run build: exit 0
• npm run lint:root: exit 0
• Re-adding the removed SSR spacing addition makes both SSR tests fail; restoring the file makes them pass.
• The null-spacing test fails on 680885e with TypeError: Cannot read properties of null (reading 'trim') and passes at ae10e84.

Not run: site install, build:site, and lint:site; this PR does not touch site/.

[Aarebecca]

@SulimanAbdulrazzaq Thanks for working on this. The direction looks good, but the CI failure is a real type error. Also, measury@0.1.5 already applies numeric letterSpacing and wordSpacing, so passing them to measure() and then adding spacingWidth again would double-count spacing in SSR. The current mocked test hides this. Could you normalize the supported CSS lengths once, avoid the extra SSR addition, and add an unmocked regression test?

[codecov-commenter]

Codecov Report

❌ Patch coverage is 82.25806% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 51.56%. Comparing base (69eae2e) to head (3ef8e01).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
src/utils/text.ts	52.17%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #252      +/-   ##
==========================================
+ Coverage   50.90%   51.56%   +0.66%     
==========================================
  Files         343      343              
  Lines       28710    28769      +59     
  Branches     2665     2711      +46     
==========================================
+ Hits        14614    14836     +222     
+ Misses      14085    13922     -163     
  Partials       11       11              

Flag	Coverage Δ
infographic	51.56% <82.25%> (+0.66%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/renderer/composites/text.ts	87.91% <100.00%> (+0.13%)	⬆️
src/types/attrs.ts	100.00% <ø> (ø)
src/utils/measure-text.ts	89.50% <100.00%> (+2.60%)	⬆️
src/utils/text.ts	85.77% <52.17%> (-3.33%)	⬇️

... and 1 file with indirect coverage changes

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[SulimanAbdulrazzaq]

@Aarebecca thanks, all of your points are addressed, plus one fix I found while re-checking:

1. Type error. measureText converts letterSpacing and wordSpacing to numbers once (resolveSpacing, px and em; src/utils/measure-text.ts:92-107 and :189-197), so measury receives numbers. CI's lint-and-build passed on 3ef8e01.
2. SSR double counting. The SSR fallback passes those numbers to measury and adds nothing afterwards (:198-202). Only the canvas branch adds spacing, because canvas measureText ignores it (:144-149); the span branch sets CSS spacing (:160-161).
3. Unmocked test. The mocked SSR assertion is gone. __tests__/unit/utils/measure-text.ssr.test.ts compares against the real measury, including em values. Re-adding the old SSR addition makes both of its tests fail.
4. New in ae10e84. getTextStyle skipped only undefined, so a null spacing value threw in formatSpacing. UpdateElementCommand stores null when undoing a spacing edit on text that had none. It now skips null as main did, with a regression test.

Validation at ae10e84 (Node 20, npm install): tsc --noEmit clean; the three spacing test files 30 passed; npm test 771 passed; npm run build and npm run lint:root succeed.