Watch: show subagent requests on the parent's card, and settle threads by swipe, Settle all and the thread screen

watch/WristCode/API/GatewayClient.swift

@@ -49,6 +49,8 @@ protocol GatewayAPI: Sendable {
     func sendMessage(hostId: String, threadId: String, text: String) async throws
     func respond(hostId: String, threadId: String, request: RespondRequest) async throws
     func stop(hostId: String, threadId: String) async throws
+    /// Settles a thread, as in T3. A settled thread that finished or failed leaves the feed.
+    func settle(hostId: String, threadId: String) async throws
     func projects() async throws -> ProjectsResponse
     func newThread(_ request: NewThreadRequest) async throws -> NewThreadResponse
     func registerPush(_ registration: PushRegistration) async throws
@@ -95,6 +97,10 @@ struct GatewayClient: GatewayAPI {
         try await callIgnoringBody("POST", ["v1", "threads", hostId, threadId, "stop"], body: nil as SendMessageRequest?)
     }
 
+    func settle(hostId: String, threadId: String) async throws {
+        try await callIgnoringBody("POST", ["v1", "threads", hostId, threadId, "settle"], body: nil as SendMessageRequest?)
+    }
+
     func projects() async throws -> ProjectsResponse {
         try await call("GET", ["v1", "projects"])
     }