Three test layers against live webinstall.dev APIs:
1. Unfiltered release API — OS/ext vocabulary, version format
2. Filtered release API — correct package for specific OS/arch
3. Installer script rendering — WEBI_* vars, download URLs
47 pass, 2 known format-preference diffs (node .pkg/.7z vs .tar.gz/.zip),
5 known Go-cache improvements (excluding .deb/.pem non-installable formats).
Compares local cache-only output against golden data fetched from
the live API. Tests OS/arch/ext vocabulary, version format, and
filtered query results for bat, go, node, rg, jq, caddy.
