Restore pasting and rename sections to workspaces

Replacing the main menu dropped the Edit menu that AppKit routes
Cmd+V/C/A/Z through, so the composer could not paste at all. The menu is
rebuilt with those items, which --diag now dumps so the wiring can be
checked without a keyboard.

Workspaces also gained an order: the Cmd+K switcher has up/down controls,
creating one opens a naming modal instead of prefilling the composer, and
the UI now says workspace throughout. The stored JSON keeps the original
`sections` keys so existing data and sync payloads stay valid.

Sources/Prompt/App.swift

@@ -32,6 +32,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         // which locks the user out once the panel is hidden.
         if CommandLine.arguments.contains("--diag") {
             setupStatusItem()
+            setupMainMenu()
             DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
                 self.writeDiagnostics()
                 NSApp.terminate(nil)
@@ -113,24 +114,40 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
     /// Accessory apps have no visible menu bar, but the main menu still
     /// services key equivalents — this is what makes Cmd+Q and Cmd+W work
     /// while the panel has focus.
+    ///
+    /// The Edit menu is not decoration: AppKit routes Cmd+C/V/X/A/Z through
+    /// these items, so a minimal main menu silently breaks pasting and
+    /// selecting in the composer.
     private func setupMainMenu() {
         let mainMenu = NSMenu()
+
         let appMenuItem = NSMenuItem()
         mainMenu.addItem(appMenuItem)
-
-        let appMenu = NSMenu()
+        let appMenu = NSMenu(title: "Prompt")
         appMenuItem.submenu = appMenu
 
         let hide = NSMenuItem(title: "Hide Panel", action: #selector(hidePanel), keyEquivalent: "w")
         hide.target = self
         appMenu.addItem(hide)
-
         appMenu.addItem(.separator())
-
         let quit = NSMenuItem(title: "Quit Prompt", action: #selector(quit), keyEquivalent: "q")
         quit.target = self
         appMenu.addItem(quit)
 
+        let editMenuItem = NSMenuItem()
+        mainMenu.addItem(editMenuItem)
+        let editMenu = NSMenu(title: "Edit")
+        editMenuItem.submenu = editMenu
+
+        editMenu.addItem(withTitle: "Undo", action: Selector(("undo:")), keyEquivalent: "z")
+        let redo = editMenu.addItem(withTitle: "Redo", action: Selector(("redo:")), keyEquivalent: "z")
+        redo.keyEquivalentModifierMask = [.command, .shift]
+        editMenu.addItem(.separator())
+        editMenu.addItem(withTitle: "Cut", action: #selector(NSText.cut(_:)), keyEquivalent: "x")
+        editMenu.addItem(withTitle: "Copy", action: #selector(NSText.copy(_:)), keyEquivalent: "c")
+        editMenu.addItem(withTitle: "Paste", action: #selector(NSText.paste(_:)), keyEquivalent: "v")
+        editMenu.addItem(withTitle: "Select All", action: #selector(NSText.selectAll(_:)), keyEquivalent: "a")
+
         NSApp.mainMenu = mainMenu
     }
 
@@ -153,6 +170,15 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
             lines.append("status item has no window (not in the menu bar)")
         }
         lines.append("preferred position: \(UserDefaults.standard.object(forKey: "NSStatusItem Preferred Position Prompt") ?? "unset")")
+        lines.append("main menu:")
+        for item in NSApp.mainMenu?.items ?? [] {
+            lines.append("  \(item.submenu?.title ?? item.title)")
+            for entry in item.submenu?.items ?? [] {
+                guard !entry.isSeparatorItem else { continue }
+                let action = entry.action.map(NSStringFromSelector) ?? "-"
+                lines.append("    \(entry.title) [\(entry.keyEquivalentModifierMask.rawValue)] \(action)")
+            }
+        }
         try? lines.joined(separator: "\n").write(
             to: URL(fileURLWithPath: "/tmp/prompt-diag.txt"), atomically: true, encoding: .utf8
         )