fix(lists): add items offline via the outbox; recognisable input field

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

frontend/src/lib/offline.ts

@@ -154,6 +154,43 @@ export function enqueue(method: OutboxEntry['method'], path: string, body: Recor
 
 export const outboxCount = () => getOutbox().length;
 
+/** Changes the body of a queued entry (e.g. the quantity of a list item added offline). */
+export function updateQueued(entryId: string, body: Record<string, unknown>): boolean {
+  const entries = getOutbox();
+  const entry = entries.find((e) => e.id === entryId);
+  if (!entry) return false;
+  entry.body = { ...entry.body, ...body };
+  saveOutbox(entries);
+  return true;
+}
+
+/** Removes a queued entry that is no longer wanted (e.g. a list item added and deleted while offline). */
+export function dropQueued(entryId: string): boolean {
+  const entries = getOutbox();
+  const rest = entries.filter((e) => e.id !== entryId);
+  if (rest.length === entries.length) return false;
+  saveOutbox(rest);
+  return true;
+}
+
+// List items added offline: a stand-in id until the server knows them, derived from the outbox entry
+export const OFFLINE_ITEM_PREFIX = 'itm_offline_';
+const LIST_ITEMS_PATH = /^\/api\/v1\/lists\/([^/]+)\/items$/;
+
+/** List items still waiting in the outbox, as stand-ins for the list view (also after a reload). */
+export function pendingListItems(): { listId: string; id: string; content: string; category: string; quantity: string; createdAt: string }[] {
+  return getOutbox()
+    .filter((e) => e.method === 'POST' && LIST_ITEMS_PATH.test(e.path))
+    .map((e) => ({
+      listId: (e.path.match(LIST_ITEMS_PATH) as RegExpMatchArray)[1],
+      id: OFFLINE_ITEM_PREFIX + e.id,
+      content: String(e.body.content || ''),
+      category: String(e.body.category || ''),
+      quantity: String(e.body.quantity || ''),
+      createdAt: e.createdAt,
+    }));
+}
+
 let flushing: Promise<number> | null = null;
 
 /**