CB-308: fold in the adversarial review; bump wiki to 4320c1c

Four new resolved decisions (§7.7-7.10): turn state split by where the signals
are, with ABANDONED explicitly belt-and-braces over the waiter timeout; the
dual ack model with spawn idempotence by construction (gid stored IN the herdr
pane — the load-bearing detail of the no-ledger position — plus an in-flight
reservation for redelivery during a slow spawn); enforced publish semantics
(confirms + mandatory on a separate channel, return-before-confirm caveat);
queue lifecycle = session lifecycle with .v2 names for the redeclare hazard.

§8 reworked: global id scheme resolved and moved up; control authorization
sharpened into the hard gate on U4 (per-host allowlist beside the peer keys);
key distribution/rotation added. New §9: implementation order, each step
verifiable single-host, U4 gated, U8 last.

Wiki pointer bumped to 4320c1c (chapter 10 same-pass changes).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013ZGgxLQ2VpwZhEYoru8rkf

docs/CB-308-Multi-Host-Federation.md

@@ -197,7 +197,9 @@ CB-308 doesn't have to repaint the topology.
 
 Settled in a design review of this note + wiki chapter 10. The broker-level operational rules
 (inbox caps, TLS + private broker, schema versioning, trace id, exclusive consumers, U8 broadcast)
-are recorded in wiki 10 §10; the CB-308-side decisions are below.
+are recorded in wiki 10 §10; the CB-308-side decisions are below. Entries 1–6 are the first-pass
+decisions; 7–10 came out of the adversarial second-pass review (same day) and supersede 1–6 where
+they overlap (notably: the envelope is no longer optional, and dedup is split by path).
 
 1. **Sender authenticity — sign every message.** Each gateway holds its own signing key and signs
    what it publishes (sender gid, `msgId`, timestamp). The receiving gateway verifies the
@@ -230,17 +232,72 @@ are recorded in wiki 10 §10; the CB-308-side decisions are below.
    deliver). Gateways auto-reconnect; remote hosts read as unknown in the roster meanwhile. Broker
    HA is a later ops choice, not a design requirement.
 
+7. **Turn state — split by where the signals are.** The *worker's* gateway owns the turn record
+   (turnId minting, ask coalescing, STALE_TURN, the completion/failure fallbacks, CB-516 abandon):
+   every input to those decisions — pane status, injection, teardown — is local to it. The
+   *sender's* gateway owns only the waiter. The two are stitched by terminal-outcome envelope
+   kinds (`REPLY` / `FAILED` / `ABANDONED`) published to the sender's inbox: a worker dying on B
+   fails A's waiter fast because gateway B sees the death synchronously and says so.
+   **`ABANDONED` is belt-and-braces over the waiter's own timeout and roster expiry, never a
+   replacement** — the case where the waiter hangs longest is gateway B itself dying, which is
+   exactly when B can publish nothing.
+8. **Dual ack model + spawn idempotence by construction.** Forward path (a brief into a worker):
+   ack **before** the inject — at-most-once, duplicates structurally impossible; the loss window
+   is closed by an `INJECTED` confirmation published after the inject lands (no `INJECTED` within
+   a bound = loud fast failure at the sender, not a silent send-timeout). Reply/pull path keeps
+   ack-after-drain — a duplicate reply is benign, deduped by `msgId`. Spawn: the requester mints
+   **spawn id = the new worker's gid**; the target checks it against the **live pane registry**,
+   and the gid is **stored in the herdr pane itself** (label/env, readable back), so a restarted
+   gateway rebuilds gid↔pane from herdr and the check survives restarts with *no persisted
+   ledger* — this storage point is the load-bearing detail of the no-ledger position. An
+   **in-flight reservation set**, entered before the launcher call, absorbs a redelivery arriving
+   while the first spawn is still inside CB-306's readiness gate; a crash mid-spawn leaves a
+   half-built pane, which is exactly what CB-117 reaps.
+9. **Publish is enforced, not fire-and-forget.** Publisher confirms + the `mandatory` flag + a
+   return listener, on a **publish channel separate from the consume/ack channel** — synchronous
+   confirms on the single shared channel would hold its lock across a broker round trip and
+   serialize acks fleet-wide. Ordering caveat: a *return* (unroutable) arrives **before** the
+   confirm, so "confirmed" ≠ "routed"; the sender checks the returned-set at confirm time.
+   `mandatory` is false only for `BROADCAST`, where an empty group is legal silence.
+10. **Queue lifecycle is session lifecycle.** `bridge_stop`/reap deletes the worker's inbox queue
+    (its `broadcast.*` bindings die with it — no broadcasts to the dead); `x-expires` collects
+    queues orphaned by a crashed gateway (long for main/orchestrator inboxes, short for workers).
+    Queue names carry a version suffix (`.v2`): AMQP refuses to redeclare an existing durable
+    queue with new arguments (`PRECONDITION_FAILED` — a crash loop on an in-place upgrade from
+    v1.0.0), and the suffix keeps old sender-keyed and new recipient-keyed queues apart during
+    the keying migration (wiki 10 §3 footnote).
+
 ## 8. Still open
 
 - **Directory ground-truth:** pure soft-state presence (heartbeats) vs. also treating broker queue
   existence as authoritative. Lean soft-state to preserve the persistence boundary; revisit if
   split-brain roster views cause mis-routing.
-- **Global id scheme:** `<host>/<paneId>` (human-legible, leaks host) vs. opaque UUID (clean, needs
-  the directory to resolve host). Probably UUID in the protocol, host as directory metadata.
 - **Gateway discovery:** how gateways find the broker and each other (static config vs. discovery).
-- **Control authorization:** signing (§7.1) settles *who sent it*; still open is *who may do
-  what* — which leaders may spawn or stop on which hosts (allowlist vs. a capability token per
-  control action — ties into CB-401 Stage-C).
+- **Control authorization — THE GATE ON U4.** Signing (§7.1) settles *who sent it*; authorization
+  is *who may do what*. **Cross-host spawn must not land before the minimal version exists**: a
+  per-host allowlist in `bridged.yaml` — beside the peer public keys — of gateway ids permitted to
+  publish control to this host, checked against the verified signature. A few lines of config and
+  check; without them, any principal holding broker credentials can start processes on every host
+  in the fleet.
+- **Key distribution & rotation:** static config (host → public key in each `bridged.yaml`) is
+  fine at the current 2–3 host scale; rotation is manual. A refinement, not a blocker.
 - **Gateway death mid-turn:** the roster reaps it by missed heartbeat, and in-flight primary-bound
   messages survive by broker durability; still open is reconciling *worker* state when the dead
   gateway's host comes back (orphaned panes vs. still-valid sessions).
+
+*(Resolved and moved up: the global id scheme — an opaque UUID minted by the spawn requester as
+the spawn id, host carried as roster metadata; §7.8.)*
+
+## 9. Implementation order (each step verifiable single-host)
+
+1. **As-built fixes, independent of CB-308** (v1.0.x tickets): `basicQos` prefetch on the AMQP
+   consumer (today the queue drains into gateway heap, so any cap would guard an empty queue);
+   publisher confirms + `mandatory` (§7.9); the `drainReplies` javadoc that claims "the ack is
+   local" — false for the AMQP adapter.
+2. Envelope + signing (wiki 10 §2.1) — testable against the single-host broker.
+3. Recipient-keyed queue migration (`.v2` names, drain-by-`from`, `ReplyPushLoop` rekeyed).
+4. Global id + queue lifecycle (§7.8, §7.10).
+5. Roster: host-level heartbeat + signed presence; then the routing fork (§3.2).
+6. U2 cross-host with the terminal-outcome kinds (§7.4, §7.7).
+7. U4 cross-host spawn — **gated on the control allowlist (§8)**.
+8. U8 broadcast **last** — it is the feature that punishes an unfinished queue lifecycle.