fix: support letter and word spacing in text

[SulimanAbdulrazzaq]

Summary

Fixes #184.

• Include letterSpacing and wordSpacing in browser and SSR text measurements.
• Preserve word-spacing through the text renderer and apply both spacing values as CSS lengths.
• Add regression coverage for canvas/SSR measurement and rendered text styles.

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

• prettier --check (passed)
• git diff --check (passed)
• Targeted Vitest and TypeScript checks were attempted, but the local dependency install is incomplete (missing ESM dependency files and malformed cached declaration files). GitHub CI should provide the clean dependency validation.

[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?