fix(acpmux): relay sends when peer link is down

Closed
TE
7d ago
+399-32

When a peer session was unreachable, acpmux send treated the peer-down marker as an immediate no-session refusal, so delivery waited for a direct path and could time out. Peer-qualified targets now remain eligible for the durable mesh relay; when the relay is unavailable, the existing outbox retry path still owns the delivery. The hub route predicate and peer-cache test cover this failover.

Validation:

  • git diff --check
  • Focused fleet run: cmux-ci test -- bash -lc 'cd cmux-tui && cargo test -p acpmux mesh_route_tests' passed at d5f2a2d376c0ce095228c122e2d4c7df0228b4af (run 40956252178).

Agent session: agent session