* New PairAttachVerifier (crates/maestro-daemon/src/jwt.rs): checks
signature, aud == self, exp > now, and sub ∈ allow_inbound. Default
deny — empty allow_inbound rejects every cross-daemon attach.
* /sessions/:id/stream tries the legacy verifier first, falls back to
the pair verifier on mismatch. Compat with existing direct-attach.
* New BrokerHandle (crates/maestro-daemon/src/broker.rs): shared between
the registry-client task and HTTP handlers; calls ResolveAttach over
the control link and correlates the reply via a pending map.
* RegistryClient now owns a BrokerHandle, drains its outbound mpsc
alongside session events / heartbeats, and routes
ResolveAttachResult back into the pending map. First heartbeat fires
immediately so the registry has the daemon's perimeter info before
the first ResolveAttach.
* /api/attach/🆔 self-owned → local PTY; peer-owned (per catalog
mirror) → ResolveAttach + T2 dial + bidirectional frame proxy.
Returns structured errors for missing local perimeter, peer on a
different perimeter, etc. T1/T3 stay stubbed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>