Start a new task from a closed task

mac/Sources/Byre/Chat.swift

@@ -134,7 +134,17 @@ final class ChatModel {
         member != nil
     }
 
+    var closed: Bool {
+        guard let taskId, let task = store.findTask(taskId) else {
+            return false
+        }
+        return task.status != .active
+    }
+
     var placeholder: String {
+        if closed {
+            return "Continue in a new task, started from main, whose agent picks up this conversation. Paste or drop images to attach them."
+        }
         if team {
             return "Post to the team's board; every agent of the team gets it."
         }
@@ -468,6 +478,14 @@ final class ChatModel {
         case .lead:
             _ = try await api.messageLead(body: .json(.init(text: text, images: images, model: sessionId != nil ? model : firstModel, sendId: sendID))).accepted
         case .task(let id):
+            if closed {
+                guard let sessionId else {
+                    throw ApiError(status: 0, message: "This task has no agent conversation to continue.")
+                }
+                let task = try await api.continueSession(path: .init(sessionId: sessionId), body: .json(.init(text: text, images: images, model: team ? nil : model, sendId: sendID))).created.body.json
+                store.focusTask(task.id)
+                return
+            }
             if team {
                 if images != nil {
                     throw ApiError(status: 0, message: "The board takes text only; drop the images to post.")