Let a queued message be taken back into the composer

mac/Sources/Byre/TranscriptBuilder.swift

@@ -135,6 +135,7 @@ struct PendingSend: Identifiable {
     let local: Bool
     let queued: Bool
     let md: [MDBlock]
+    var inputId: Int? = nil
 }
 
 @MainActor
@@ -231,6 +232,10 @@ final class TranscriptBuilder {
         }
     }
 
+    func withdrawn(_ inputId: Int) {
+        pending.removeAll { $0.inputId == inputId }
+    }
+
     private func confirmPending(_ text: String, queued: Bool, local: Bool) {
         let i = queued ? pending.firstIndex { !$0.local && $0.text == text } : nil
         if let i = i ?? (local ? pending.firstIndex { $0.local && $0.text == text } : nil) {
@@ -417,7 +422,13 @@ final class TranscriptBuilder {
                     confirmPending(text, queued: false, local: true)
                     pendingIds += 1
                     let images = (p["images"] as? [(any Sendable)?] ?? []).map { jsString($0) }
-                    pending.append(PendingSend(id: pendingIds, text: text, images: [], imageIds: images, local: false, queued: true, md: trimmed(text).isEmpty ? [] : parseMarkdown(text)))
+                    pending.append(PendingSend(id: pendingIds, text: text, images: [], imageIds: images, local: false, queued: true, md: trimmed(text).isEmpty ? [] : parseMarkdown(text), inputId: int(p, "id")))
+                }
+                continue
+            }
+            if ev.kind == "user.unqueued" {
+                if sink == nil, let id = int(p, "id") {
+                    withdrawn(id)
                 }
                 continue
             }