Summary

• The Update browserslist cron has been failing (example) because the Rust codegen reads from caniuse-db while the parser tests shell out to the JS browserslist CLI, which reads from caniuse-lite. Both packages share a 1.0.30001NNN version number but their data snapshots drift, so a pnpm update --prod leaves the two data sources misaligned and the parser tests diff against a different Firefox/Chrome version set than the one baked into the generated Rust data.
• Aligns both sides on caniuse-lite by porting caniuse-lite's three JS unpackers (agents, feature, region) to Rust under xtask/src/data/caniuse_lite.rs. The new loader reads the packed module.exports = {...} data files via JSON5, expands the single-letter browser/version codes, and produces the same Caniuse shape the existing generators consume — no Node spawning at codegen time.
• Regions now flow through Caniuse instead of being read per-file from disk; the regions generator drops its fs::read_dir over caniuse-db/region-usage-json/.
• package.json swaps caniuse-db for caniuse-lite as a peer dep; the cron's pnpm update --prod continues to keep the lockfile fresh.

Notes

• caniuse-lite's F (release_date) map has null for some versions, so release_date is typed IndexMap<String, Option<i64>>.
• A few feature files use D:undefined, which isn't JSON5, so the parser does body.replace("undefined", "null") before deserializing.
• 583 feature files + 240 region files are read and parsed at codegen time; the full run completes in ~200ms locally.