Open on startup by default and block duplicate workspace names

- LoginItem registers on the first bundled launch, so the app opens on
  startup without the user finding the toggle; a user who turns it off is
  never overridden. A never-registered bundle reports SMAppService .notFound
  rather than .notRegistered, so the guard only treats enabled/approval as
  done. --diag now prints the raw status.
- New Workspace refuses a name that already exists (case-insensitive) and
  says so inline; Return cannot bypass it. The composer's '# Name' still
  switches to the existing workspace, which is the quick-capture gesture.

AGENTS.md

@@ -13,8 +13,10 @@ clicking an item copies it back to the clipboard.
   `NSStatusItem Preferred Position Prompt`). Left click toggles the panel,
   right click shows the menu (accessibility state, launch at login, open data
   folder, quit). Contains the single-instance guard and `LoginItem`
-  (`SMAppService`). The sync panel also carries a Launch at Login toggle (the
+  (`SMAppService`): the app auto-registers as a login item on the first
-  app's only settings surface). Also sets `NSApp.mainMenu` with Hide Panel (Cmd+W) and Quit
+  bundled launch (once, tracked by `loginItem.autoRegistered` in UserDefaults)
+  so it opens on startup by default; the Launch at Login toggle in the sync
+  panel (the app's only settings surface) is the opt-out. Also sets `NSApp.mainMenu` with Hide Panel (Cmd+W) and Quit
   (Cmd+Q) — an accessory app shows no menu bar, but the main menu still
   services key equivalents, which is the only way to quit from the keyboard
   while the panel has focus. `applicationShouldHandleReopen` shows the panel so
@@ -239,6 +241,11 @@ brew upgrade --cask prompt
   populated when the command fires.
 - `captureSelection()` blocks up to 0.5s polling the pasteboard — keep it off
   the main thread (the hotkey handler already dispatches to a global queue).
+- **`SMAppService.mainApp.status` is `.notFound` for a bundle BTM has never
+  seen**, not `.notRegistered`, and `register()` still works from that state.
+  Only treat `.enabled` and `.requiresApproval` as "already done"; checking for
+  `.notRegistered` silently skips the registration. `Prompt --diag` prints the
+  raw status.
 - The double-Shift tap needs Accessibility; without it the event tap silently
   fails and only the Carbon fallbacks work. The panel banner and the status
   menu both surface the permission state, and `AppDelegate` shows a launch

Sources/Prompt/App.swift

@@ -61,6 +61,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
 
         setupStatusItem()
         promptForAccessibilityIfNeeded()
+        LoginItem.autoRegisterOnce()
 
         // Let SwiftUI finish installing its main menu, then augment it.
         DispatchQueue.main.async { self.installMenuItems() }
@@ -140,6 +141,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
     @MainActor
     private func writeDiagnostics() {
         var lines = ["Prompt diagnostics", "accessibility: \(AXIsProcessTrusted())"]
+        lines.append("login item status: \(SMAppService.mainApp.status.rawValue)")
         if let window = statusItem?.button?.window {
             lines.append("status item frame: \(window.frame)")
             if let screen = window.screen ?? NSScreen.main {
@@ -266,6 +268,31 @@ enum LoginItem {
         SMAppService.mainApp.status == .enabled
     }
 
+    /// Registers the app as a login item on first launch so Prompt opens on
+    /// startup without the user hunting for the toggle. Runs once (tracked in
+    /// UserDefaults) so a user who disables it is never overridden, and skips
+    /// `swift run`, where there is no bundle to register.
+    static func autoRegisterOnce() {
+        let key = "loginItem.autoRegistered"
+        guard Bundle.main.bundleIdentifier != nil,
+              !UserDefaults.standard.bool(forKey: key) else { return }
+        // A never-registered bundle reports `.notFound` on current macOS
+        // (BTM has no record), not `.notRegistered`, so only skip when there
+        // is nothing left to do.
+        switch SMAppService.mainApp.status {
+        case .enabled, .requiresApproval:
+            UserDefaults.standard.set(true, forKey: key)
+        default:
+            do {
+                try SMAppService.mainApp.register()
+                UserDefaults.standard.set(true, forKey: key)
+                NSLog("Prompt: registered as a login item (%d)", SMAppService.mainApp.status.rawValue)
+            } catch {
+                NSLog("Prompt: login item registration failed: %@", error.localizedDescription)
+            }
+        }
+    }
+
     static func toggle() -> Bool {
         let service = SMAppService.mainApp
         do {

Sources/Prompt/PanelView.swift

@@ -616,6 +616,19 @@ struct PanelView: View {
 
     // MARK: - New workspace
 
+    private var trimmedWorkspaceName: String {
+        newWorkspaceName.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    /// Case-insensitive, like the store's dedupe. The modal blocks creation
+    /// with a hint instead of silently switching to the existing workspace.
+    private var workspaceNameExists: Bool {
+        let name = trimmedWorkspaceName
+        return !name.isEmpty && store.sections.contains {
+            $0.name.caseInsensitiveCompare(name) == .orderedSame
+        }
+    }
+
     @ViewBuilder
     private var newWorkspaceModal: some View {
         if showNewWorkspace {
@@ -630,12 +643,17 @@ struct PanelView: View {
                         .focused($focusedField, equals: .newWorkspace)
                         .onSubmit(createWorkspace)
                         .onExitCommand { dismissNewWorkspace() }
+                    if workspaceNameExists {
+                        Text("A workspace named “\(trimmedWorkspaceName)” already exists.")
+                            .font(.caption)
+                            .foregroundStyle(.red)
+                    }
                     HStack {
                         Spacer()
                         Button("Cancel") { dismissNewWorkspace() }
                         Button("Create") { createWorkspace() }
                             .keyboardShortcut(.defaultAction)
-                            .disabled(newWorkspaceName.trimmingCharacters(in: .whitespaces).isEmpty)
+                            .disabled(trimmedWorkspaceName.isEmpty || workspaceNameExists)
                     }
                 }
                 .padding(16)
@@ -649,8 +667,8 @@ struct PanelView: View {
     }
 
     private func createWorkspace() {
-        let name = newWorkspaceName.trimmingCharacters(in: .whitespacesAndNewlines)
+        let name = trimmedWorkspaceName
-        guard !name.isEmpty else { return }
+        guard !name.isEmpty, !workspaceNameExists else { return }
         store.createSection(named: name)
         dismissNewWorkspace()
     }