chore(cache): disable unused zstd default features

[fengmk2]

Motivation

vt depends on zstd with its default features (legacy, arrays, zdict_builder). The cache only streams archives that vt writes itself through zstd::Encoder and zstd::Decoder, including the ones restored from a remote cache. It never decodes the pre-1.0 zstd frame formats, builds dictionaries, or uses the array helpers. The legacy decoders were still linked, because libzstd's streaming decoder calls them whenever legacy support is compiled in.

This matches astral-sh/uv#22242, which disabled unused Zstandard support in uv-build.

Disabling the defaults shrinks the Vite+ NAPI binding (vite-plus-cli --features rolldown, release profile, darwin-arm64) from 42,115,952 to 41,950,544 bytes, a 165,408-byte (0.39%) reduction. The baseline patches an unmodified vite-task checkout into vite-plus the same way. Only zstd-safe/std remains enabled, and Cargo.lock is unchanged. Vite+ picks this up with its next vite-task bump.

🤖 Generated with Claude Code

[github-actions]

fspy benchmark

linux

dynamic/launch             change  +0.75%  [ -8.19% ..  +9.73%]  overhead   +55.64%
dynamic/access             change  +0.18%  [ -4.02% ..  +4.48%]  overhead    +9.11%
dynamic/access-relative    change  +0.46%  [-10.44% .. +11.99%]  overhead   +48.23%
dynamic/access-contended   change  +1.33%  [ -2.32% ..  +6.58%]  overhead   +11.10%
static/launch              change  +0.32%  [ -5.54% ..  +7.91%]  overhead  +170.33%
static/access              change  -0.23%  [ -6.28% ..  +3.81%]  overhead  +719.41%
static/access-relative     change  +0.78%  [ -5.80% ..  +6.41%]  overhead +1222.33%
static/access-contended    change  -1.18%  [-11.44% ..  +4.75%]  overhead +2110.63%

macos

dynamic/launch             change  +0.23%  [ -6.26% ..  +8.61%]  overhead  +232.23%
dynamic/access             change  +0.90%  [-13.88% .. +19.81%]  overhead    +3.59%
dynamic/access-relative    change  -0.12%  [-32.54% .. +40.91%]  overhead  +269.85%
dynamic/access-contended   change +10.53%  [-12.50% .. +133.98%]  overhead    +2.99%

windows

dynamic/launch             change  -0.09%  [ -2.65% ..  +1.91%]  overhead   +25.04%
dynamic/access             change  +0.00%  [ -0.92% ..  +0.75%]  overhead    +1.17%
dynamic/access-relative    change  -0.18%  [ -0.91% ..  +0.92%]  overhead    +1.13%
dynamic/access-contended   change  +0.19%  [ -1.41% ..  +1.10%]  overhead    +1.45%