Clause 1: proactive refresh at T-90s (serve gate + spawn_proactive_refresh).
Clause 2: universal 401 retry driver (with_token_retry + Attempt) — reads AND
writes; double-401 terminal AuthDegraded; 403 stays terminal.
Clause 3: real-exp audit — Interactive refresh persists real JWT exp.

Chain: HEAD a9d8ec8 == tag v0.5.9 == Cargo.toml 0.5.9 == crates.io 0.5.9.
Tests: 181 green (lib 161, doc 4, integration 16). Semver 0.5.9-not-0.6.0:
consumers pin pep="0.5". thq v0.9.2 parity UNVERIFIED (no local source).