Build the welcome screen

The welcome window becomes the real thing: Xcode-style, hidden title
bar with background drag, branding and actions left, recents right —
rows carrying the board symbol, name, location, and the registry's
cached lane/card counts (stamped at close, never a scan at welcome
time), sorted by last opened. Launch failures surface row-level per
02: a failure joins its recents row as a warning caption, an
unresolvable bookmark renders unavailable with Forget its one
affordance, and only a failure with no row to carry it falls back to
a compact list; a board opening again heals its row. New Board
(Opt-Cmd-N) opens the Pages-style template chooser — shipped with
the single Basic template and the m9 seams marked — flowing through
the save panel into createBoard/createLane and straight into a board
window. Open Recent gains its submenu with Clear Menu (byte-identical
to forgetting every row, pinned by test), and File > Duplicate forks
the frontmost board to a Finder-style copy sibling: pending work
flushes first through the close flush's step two alone (sessions stay
open — 09's stated exception), every GUID and tombstone carries (the
whole-board carve-out from copies-remint), and the copy opens in its
own window while the original stays put. 36 new tests.

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

Kanban/KanbanApp.swift

@@ -55,11 +55,30 @@ struct KanbanApp: App {
         }
         .defaultLaunchBehavior(shouldRestoreAtLaunch ? .suppressed : .automatic)
         .restorationBehavior(.disabled)
-        .windowResizability(.contentSize)
+        // "Welcome: resizable, no title bar (background drag)" (03-board-ui.md § Welcome screen &
+        // templates). `.contentMinSize` rather than `.contentSize`, because the view states a
+        // *minimum* and the recents list is meant to take whatever space the user gives it; the
+        // hidden title bar is why `WelcomeView` carries a `WindowDragGesture`.
+        .windowResizability(.contentMinSize)
+        .defaultSize(width: 820, height: 500)
+        .windowStyle(.hiddenTitleBar)
         // Its automatic Window-menu item is replaced by the explicit command below, so the title is
         // the one 11-command-nexus.md names rather than whatever the scene happens to be called.
         .commandsRemoved()
 
+        // The template chooser (09-templates.md), reached from File ▸ New Board… ⌥⌘N and from
+        // welcome's own button. A `Window` for welcome's reason — there is one of it, ever — and
+        // suppressed at launch, since ⌥⌘N is the only thing that ever asks for it.
+        Window("New Board", id: WindowID.templateChooser) {
+            TemplateChooserView()
+                .environment(appModel)
+                .captureWindowActions(into: appModel)
+        }
+        .defaultLaunchBehavior(.suppressed)
+        .restorationBehavior(.disabled)
+        .windowResizability(.contentSize)
+        .commandsRemoved()
+
         Window("", id: WindowID.restoreBootstrap) {
             RestoreBootstrapView()
                 .environment(appModel)
@@ -107,13 +126,15 @@ struct KanbanApp: App {
     /// changing one silently breaks every remap of it.
     @CommandsBuilder
     private var menuCommands: some Commands {
-        // The File group, in 11-command-nexus.md's own row order: New Card, New Lane, (New Board…,
-        // still owed), Open…, (Open Recent, still owed), Board Info, (Duplicate / Save as Template /
-        // Reveal in Finder, still owed), then the trash trio and Empty Trash…. Every one of them
-        // validates against the frontmost board through the focus system, so each is simply
-        // absent-of-effect when no board is in front.
+        // The File group, in 11-command-nexus.md's own row order: New Card, New Lane, New Board…,
+        // Open…, Open Recent ▸, Board Info, Duplicate, (Save as Template, still owed — 09),
+        // Reveal in Finder, then the trash trio and Empty Trash…. The board-scoped ones validate
+        // against the frontmost board through the focus system, so each is simply absent-of-effect
+        // when no board is in front; New Board… and Open Recent are available everywhere, including
+        // with no window at all.
         CommandGroup(after: .newItem) {
             BoardCreationCommands()
+            NewBoardCommand(appModel: appModel)
 
             Divider()
 
@@ -122,12 +143,19 @@ struct KanbanApp: App {
             }
             .keyboardShortcut("o", modifiers: .command)
 
+            OpenRecentMenu(appModel: appModel)
+
             Divider()
 
             BoardInfoCommand()
 
             Divider()
 
+            DuplicateBoardCommand(appModel: appModel)
+            RevealInFinderCommand()
+
+            Divider()
+
             TrashCommands()
         }