Make pasting reliable and turn items into checkboxes

Pasting still failed because the panel is a nonactivating panel: it can
be key while the app is not active, and menu key equivalents are not
delivered reliably in that state. Cmd+V is now dispatched to the
responder chain directly, and the app no longer replaces SwiftUI's main
menu — it only adds Hide Panel to it, so the Edit items that AppKit
routes text shortcuts through stay intact.

Rows also gained a checkbox so a workspace works as a checklist without
turning the row into a button, which would swallow the checkbox's clicks.

Sources/Prompt/PanelView.swift

@@ -193,8 +193,21 @@ struct PanelView: View {
         .padding(.vertical, 48)
     }
 
+    /// Rows are checklists by default: a checkbox to tick an item off, with the
+    /// rest of the row copying on click. The row cannot be a Button because the
+    /// checkbox is one, and nested buttons do not receive clicks.
     private func row(for item: PromptItem, sectionName: String) -> some View {
-        Button { handleClick(item) } label: {
+        HStack(alignment: .top, spacing: 8) {
+            Button {
+                store.toggleDone(item.id)
+            } label: {
+                Image(systemName: item.done ? "checkmark.circle.fill" : "circle")
+                    .font(.system(size: 15))
+                    .foregroundStyle(item.done ? Color.accentColor : Color.secondary.opacity(0.55))
+            }
+            .buttonStyle(.plain)
+            .help(item.done ? "Mark as not done" : "Mark as done")
+
             VStack(alignment: .leading, spacing: 6) {
                 if !sectionName.isEmpty {
                     Text(sectionName.uppercased())
@@ -208,29 +221,28 @@ struct PanelView: View {
                         Text(sourceApp)
                     }
                     Text(item.createdAt, style: .time)
-                    if item.done {
-                        Image(systemName: "checkmark")
-                    }
                 }
                 .font(.caption2)
                 .foregroundStyle(.tertiary)
             }
-            .padding(10)
             .frame(maxWidth: .infinity, alignment: .leading)
-            .background(rowBackground(item))
-            .cornerRadius(8)
-            .overlay(alignment: .topTrailing) {
-                if copiedID == item.id {
-                    Label("Copied", systemImage: "checkmark.circle.fill")
-                        .font(.caption2)
-                        .foregroundStyle(.green)
-                        .padding(6)
-                        .transition(.opacity)
-                }
+        }
+        .padding(10)
+        .frame(maxWidth: .infinity, alignment: .leading)
+        .background(rowBackground(item))
+        .cornerRadius(8)
+        .overlay(alignment: .topTrailing) {
+            if copiedID == item.id {
+                Label("Copied", systemImage: "checkmark.circle.fill")
+                    .font(.caption2)
+                    .foregroundStyle(.green)
+                    .padding(6)
+                    .transition(.opacity)
             }
         }
-        .buttonStyle(.plain)
-        .help("Click to copy · Cmd+click to select several · Shift+click for a range · right-click for more")
+        .contentShape(Rectangle())
+        .onTapGesture { handleClick(item) }
+        .help("Click to copy · checkbox to tick off · Cmd+click to select several · Shift+click for a range · right-click for more")
         .contextMenu { contextMenu(for: item) }
     }