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/host/apiproxy/tests/api-proxy-commands.spec.ts

@@ -63,7 +63,7 @@ async function harness(options: { commands?: boolean; skills?: boolean } = {}):
 /** Register a live structural agent stub (api-proxy-view precedent: only id/session/status/ctx are read). */
 function stubAgent(ctx: Context, sessionId?: SessionId): Agent {
   const session = ctx.sessions.create(sessionId)
-  const inbox = new Inbox(session, { inserted: () => {}, discarded: () => {} })
+  const inbox = new Inbox(session, { inserted: () => {}, discarded: () => {}, claimed: () => {} })
   const agent = {
     id: session.id,
     session,

packages/host/apiproxy/tests/api-proxy-projections.spec.ts

@@ -54,7 +54,7 @@ async function harness(withRegistry: boolean): Promise<{ ctx: Context; session:
   if (withRegistry) await ctx.plugin(SessionProjectionRegistry)
   const session = ctx.sessions.create()
   // The gateway reads both the session and durable inbox baseline.
-  ctx.agents.register({ id: session.id, session, inbox: new Inbox(session, { inserted: () => {}, discarded: () => {} }), status: 'idle', ctx } as Agent)
+  ctx.agents.register({ id: session.id, session, inbox: new Inbox(session, { inserted: () => {}, discarded: () => {}, claimed: () => {} }), status: 'idle', ctx } as Agent)
   return { ctx, session }
 }
 

packages/host/apiproxy/tests/api-proxy-workspace.spec.ts

@@ -44,7 +44,7 @@ function stubAgent(session: Session): Agent {
     id: session.id,
     options: {},
     session,
-    inbox: new Inbox(session, { inserted: () => {}, discarded: () => {} }),
+    inbox: new Inbox(session, { inserted: () => {}, discarded: () => {}, claimed: () => {} }),
     status: 'idle',
     ctx: new Context(),
     send: () => {},