refactor(agent): publish agent/inbox/claimed from Inbox.claim

Move the claimed-message notification loop out of the loop's pre-step
into Inbox.claim(target, turn), so the step-boundary operation publishes
its own claimed notifications like insertions and discards do.

packages/pty/tool-bash-persistent/tests/loader-composition.spec.ts

@@ -43,7 +43,7 @@ function agent(ctx: Context, cwd: string): Agent {
     id,
     options: {},
     session,
-    inbox: new Inbox(session, { inserted: () => {}, discarded: () => {} }),
+    inbox: new Inbox(session, { inserted: () => {}, discarded: () => {}, claimed: () => {} }),
     status: 'idle',
     ctx: scope.ctx,
     send: () => {},