Unify list and edit-mode handler flows in input helpers

client/src/input/editSession.ts

@@ -0,0 +1,7 @@
+export type EditSessionAction = 'submit' | 'cancel' | null;
+
+export function getEditSessionAction(code: string): EditSessionAction {
+  if (code === 'Enter') return 'submit';
+  if (code === 'Escape') return 'cancel';
+  return null;
+}

client/src/input/listController.ts

@@ -0,0 +1,34 @@
+import { cycleIndex, findNextIndexByInitial } from './listNavigation';
+
+export type ListControlResult =
+  | { type: 'move'; index: number; reason: 'arrow' | 'initial' }
+  | { type: 'select' }
+  | { type: 'cancel' }
+  | { type: 'none' };
+
+export function handleListControlKey<T>(
+  code: string,
+  key: string,
+  entries: readonly T[],
+  currentIndex: number,
+  labelFor: (entry: T) => string,
+): ListControlResult {
+  if (entries.length === 0) return { type: 'none' };
+
+  if (code === 'ArrowDown' || code === 'ArrowUp') {
+    return {
+      type: 'move',
+      index: cycleIndex(currentIndex, entries.length, code === 'ArrowDown' ? 'next' : 'prev'),
+      reason: 'arrow',
+    };
+  }
+
+  const nextByInitial = findNextIndexByInitial(entries, currentIndex, key, labelFor);
+  if (nextByInitial >= 0) {
+    return { type: 'move', index: nextByInitial, reason: 'initial' };
+  }
+
+  if (code === 'Enter') return { type: 'select' };
+  if (code === 'Escape') return { type: 'cancel' };
+  return { type: 'none' };
+}