test: deterministic failover matrix — cooldown re-admission, alias chains, policies

Phase 2: proves ADR-0006/0008 semantics end to end with the fake provider
and fake clock (cooldown expiry, backoff growth, inline-alias failover,
permanent-error policies, retry budgets, bench-mid-request, exhaustion
reporting, custom classifier, chain-of-one parity).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

progress.md

@@ -1,5 +1,22 @@
 # progress
 
+## 2026-06-10 — Phase 2: health + failover chain, proven
+
+**Landed:** the full deterministic failover test matrix over the fake
+provider + fake clock (no sleeps, no network): single-transient recovery
+via same-target retry; repeated transients bench + advance; cooldown expiry
+re-admits and success resets; backoff doubling across bench rounds;
+mixed chain with an inline-expanded alias element failing over through the
+expanded targets; permanent-policy default (fail-fast on auth) and
+`AdvanceOnPermanent` override; `TransientRetries` disabled/custom; retry
+loop stops early when the tracker benches mid-request; exhaustion error
+lists skipped-while-benched targets; custom classifier override; chain-of-
+one gets identical semantics; HTTP 529 fails over. Implementation needed no
+changes — Phase 1's executor held up.
+
+**Next:** Phase 3 — OpenAI/Anthropic/Ollama/foreman REST clients + media
+pipeline.
+
 ## 2026-06-10 — Phase 1: foundations, ADRs, skeleton, docs
 
 **Landed:**