apt-audit.js scans EVERY file in apt.conf.d for Acquire::*::Proxy, classifying:
- creds: embedded userinfo (plaintext leak + stale-cred hammering risk)
- overrides: sorts after 80proxy-bridge so apt last-wins REPLACES the bridge URL
- external: points at a non-bridge proxy
Installer Legacy section alerts + fixes (backup kept: *.disabled-by-proxy-bridge).
New 'install.js doctor [--fix]': audits apt, bashrc, snap, service drop-ins,
service state, keyring presence; exit 1 when issues found.
Update semantics: deploy writes .installed-from (git commit + file hashes);
runtime JSONs are never created if present and never overwritten; tests prove
3 consecutive installs leave runtime state byte-identical. Downgrade protection
comes from the visible marker + diff reporting, never silent clobbering.
Tests: 6 audit + 2 installer (update-semantics, doctor) — suite now 23/23.
