feat(website): add shared font converter and optimizer workbench

[ayuhito]

Summary

• replace the standalone converter UI with one shared converter and optimizer workbench
• add a dedicated /tools/optimizer entry point while keeping both tools connected through the same interface
• support multi-family batches, large file sets, output customization, progress, per-family results, and local ZIP downloads
• extend the core build path to normalize compressed input, preserve all characters and variable axes, and prevent distinct fonts from overwriting the same output filename
• add the optimizer to the tools index, sitemap, metadata, and prerendered routes

Why

Conversion and webfont optimization share most of the same file inspection, format selection, processing, and download workflow. Keeping them in one workbench removes duplicate UI and processing logic while still giving each task a focused, indexable route.

All font processing remains local to the browser. The optimizer defaults to WOFF2 and ready-to-use CSS, while the converter keeps direct format conversion as its simpler default.

User impact

• users can switch between conversion and optimization without relearning the interface
• large batches are grouped by family and remain manageable through progressive disclosure
• TTF, OTF, WOFF, and WOFF2 inputs can be rebuilt into full-character webfont packages
• generated CSS supports configurable font-display and font paths
• conflicting source faces fail explicitly instead of silently overwriting an output file

Validation

• pnpm --dir packages/core test:unit — 102 tests passed
• pnpm --dir website typecheck
• pnpm check
• pnpm --dir website build — including prerendered /tools, /tools/converter, and /tools/optimizer
• manual browser walkthroughs of converter and optimizer empty, upload, settings, processing, result, mobile, invalid-file, variable-font, and 32-file states

[cloudflare-workers-and-pages]

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Status	Name	Latest Commit	Updated (UTC)
✅ Deployment successful! View logs	fontsource-api	e5fb196	Jul 20 2026, 08:06 AM

[cloudflare-workers-and-pages]

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	fontsource-website	e5fb196	Commit Preview URL Branch Preview URL	Jul 20 2026, 08:07 AM