fix(orchestrator-core): F-Q-006 + F-Q-010 InboxRegistry expect on poison

InboxRegistry::register returned (Uuid, Receiver) even when the inner
Mutex was poisoned — `if let Ok(mut g) = self.inner.lock()` swallowed
the error, the sender was never inserted, the later deliver(id, …)
saw no entry and returned Abandoned, and the caller's `await rx`
blocked until the orchestrator's outer timeout.

Sister registries (RouteTable, AppDomainTable) already .expect()
panic on poison. Make InboxRegistry::{register, cancel, deliver} loud
in the same way.

A poisoned Mutex means a prior panic inside a critical section — the
process is unrecoverable; silently swallowing it just defers the
crash and corrupts the inbox protocol on the way.

AUDIT.md anchors: F-Q-006 (register), F-Q-010 (consistency policy).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/orchestrator-core/src/inbox.rs

@@ -42,13 +42,21 @@ impl InboxRegistry {
     /// Allocate a new inbox id and register the sender side. The
     /// caller awaits the returned `Receiver`; the dispatcher delivers
     /// the outcome via `deliver(id, …)`.
+    ///
+    /// F-Q-006: panic on poison — a poisoned mutex means a prior panic
+    /// inside the lock-holding code path, so the process is unrecoverable.
+    /// Silently swallowing it (the old behaviour) leaked a dead id: the
+    /// sender never got inserted, the later `deliver(id, …)` saw no
+    /// entry and returned Abandoned, and the caller's `await rx` blocked
+    /// until the orchestrator's outer timeout. Sister registries
+    /// (RouteTable, AppDomainTable) already `.expect()` here — settle
+    /// on the same loud policy.
     #[must_use]
     pub fn register(&self) -> (Uuid, oneshot::Receiver<InboxResult>) {
         let id = Uuid::new_v4();
         let (tx, rx) = oneshot::channel();
-        if let Ok(mut g) = self.inner.lock() {
-            g.insert(id, tx);
-        }
+        let mut g = self.inner.lock().expect("inbox registry poisoned");
+        g.insert(id, tx);
         (id, rx)
     }
 
@@ -56,10 +64,8 @@ impl InboxRegistry {
     /// Drops the sender so any future `deliver` returns `Abandoned`.
     /// Returns `true` if the receiver was still registered.
     pub fn cancel(&self, id: Uuid) -> bool {
-        self.inner
-            .lock()
-            .map(|mut g| g.remove(&id).is_some())
-            .unwrap_or(false)
+        let mut g = self.inner.lock().expect("inbox registry poisoned");
+        g.remove(&id).is_some()
     }
 }
 
@@ -72,9 +78,9 @@ impl Default for InboxRegistry {
 #[async_trait]
 impl InboxResolver for InboxRegistry {
     async fn deliver(&self, inbox_id: Uuid, result: InboxResult) -> InboxDeliveryOutcome {
-        let Ok(mut g) = self.inner.lock() else {
-            return InboxDeliveryOutcome::Abandoned;
-        };
+        // F-Q-006 + F-Q-010: panic on poison, matching the registry's
+        // register/cancel policy and the sister registries.
+        let mut g = self.inner.lock().expect("inbox registry poisoned");
         let Some(tx) = g.remove(&inbox_id) else {
             return InboxDeliveryOutcome::Abandoned;
         };