Build the menu bar per the Command Nexus

Nexus parity, audited row by row (11-command-nexus.md § Menu commands) —
every already-built item's title, chord, and placement matched exactly;
this pass fills what remained:

- The future-window rows, present with stable titles and validation-driven
  disablement until their milestones fill the actions: Save as Template
  (m9), Add Attachment… ⇧⌘A, Find Next/Previous ⌘G/⇧⌘G, the View-menu
  card triplet Edit Body ⌘E / Raw Source ⌥⌘E / History (m6), Board ▸
  Pull/Push (git milestones) — one shared disabled-row shape in
  FutureCommands.swift so later milestones only flip validation.
- No Print story in v1: the print group is removed.
- Help carries the Nexus's one remap-teaching line — Customize Keyboard
  Shortcuts…, opening System Settings' Keyboard ▸ Shortcuts extension
  directly (the modern extension URL, verified to launch the appex).
- The launch-restore decision now runs through a pure, tested
  AppModel.shouldRestoreAtLaunch gate; the Settings pane's caption rides a
  proper Form section footer.

904 unit tests.

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

Kanban/App/WelcomeView.swift

@@ -358,7 +358,11 @@ struct SettingsView: View {
 
     var body: some View {
         Form {
-            Toggle("Restore open boards at launch", isOn: $restoreOpenBoardsAtLaunch)
+            Section {
+                Toggle("Restore open boards at launch", isOn: $restoreOpenBoardsAtLaunch)
+            } footer: {
+                Text("On, the boards open at your last quit reopen automatically. Off, every launch starts at Welcome.")
+            }
         }
         .formStyle(.grouped)
         .frame(width: 420)