Focus the machine table when it appears (#535)

The table is not in the window at launch: the machines view shows an empty placeholder until the first `vm list` returns, and only then swaps in the Table and has the library select the first machine. By then the window has already chosen its first responder, and nothing moves focus to the new table, so AppKit draws the selection unemphasized, in gray, instead of in the accent color.

The table now takes focus through a FocusState when it appears. When it comes back because a search matches again, the search field keeps the keyboard.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

VPhoneLaunchpad/VPhoneLaunchpad/Machines/VPhoneLaunchpadMachinesView.swift

@@ -33,6 +33,11 @@ struct VPhoneLaunchpadMachinesView: View {
     @State private var filter = ""
     /// Empty keeps the order `vm list` returns; a header click replaces it.
     @State private var sortOrder: [KeyPathComparator<VPhoneLaunchpadMachine>] = []
+    /// The table appears only once `vm list` returns, after the window has
+    /// picked its first responder, so nothing focuses it by itself. Unfocused,
+    /// AppKit draws the library's automatic selection in gray, not in the
+    /// accent color.
+    @FocusState private var tableIsFocused: Bool
 
     private var library: VPhoneLaunchpadMachineLibrary {
         model.machines
@@ -353,6 +358,14 @@ struct VPhoneLaunchpadMachinesView: View {
         } primaryAction: { paths in
             start(library.machines.filter { paths.contains($0.path) && library.state(of: $0.path) == .stopped })
         }
+        .focused($tableIsFocused)
+        .onAppear {
+            // The table comes back when a search matches again; the search
+            // field keeps the keyboard then.
+            if !(NSApp.keyWindow?.firstResponder is NSText) {
+                tableIsFocused = true
+            }
+        }
     }
 
     @ViewBuilder