fix(producer): skip slow TTC recompression

[miguel-heygen]

What

Skip wawoff2 recompression for TTC font collections and embed them as raw font/collection data URIs with the matching CSS format(collection) hint.

Why

A reported 120-second talking-head package spent about six extra minutes compiling a TTC font. Reproduction with a 19 MB Noto Sans CJK collection took 57.73 seconds and about 320 MB RSS in fontToDataUri alone. Chromium also rejects a raw collection when it is mislabeled as format(woff2).

How

• Return TTC buffers directly as font/collection instead of attempting whole-collection WOFF2 compression.
• Select format(collection) for collection data URIs while preserving format(woff2) everywhere else.
• Add regression coverage for the no-compression path and CSS format selection.

The same real TTC now embeds in 0.07 seconds with the correct data URI prefix.

Test plan

• 37 focused deterministic-font and compression tests pass
• Producer typecheck
• Formatting check on the four changed files
• Pre-commit lint, format, fallow, tracked-artifact, and typecheck hooks
• Real 19 MB NotoSansCJK-Regular.ttc benchmark: 57.73s before, 0.07s after
• Chromium validation: raw font/collection with format(collection) loads; format(woff2) does not
• Independent review: no findings