fix: no-op unknown removal, earlier-duplicate editor check, list focus for delete/undo

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Sources/Sst/DictionaryView.swift

@@ -21,6 +21,7 @@ struct DictionaryView: View {
     @State private var selection: UUID?
     @State private var editing: EditorTarget?
     @FocusState private var searchFocused: Bool
+    @FocusState private var listFocused: Bool
 
     var body: some View {
         VStack(spacing: Layout.panelGap) {
@@ -77,14 +78,25 @@ struct DictionaryView: View {
                     ForEach(list.visibleRows) { row in
                         DictionaryRow(row: row, isSelected: selection == row.id)
                             .onTapGesture(count: 2) { editing = .existing(row.id) }
-                            .onTapGesture { selection = row.id }
+                            .onTapGesture {
+                                selection = row.id
+                                listFocused = true
+                            }
                     }
                 }
             }
         }
         .focusable()
+        .focused($listFocused)
+        .focusEffectDisabled()
         .onDeleteCommand {
-            if let id = selection { list.remove(id: id) }
+            if let id = selection {
+                list.remove(id: id)
+                selection = nil
+            }
+        }
+        .onChange(of: list.rows) { _, rows in
+            if let s = selection, !rows.contains(where: { $0.id == s }) { selection = nil }
         }
         .onKeyPress(KeyEquivalent("z"), phases: .down) { press in
             guard press.modifiers == .command, list.canUndo else { return .ignored }