Distinguish picked-up from removed shopping list items

Soft-remove items via RemovedAt/RemovedByUserId instead of hard
deleting so the row survives for undo and future history reporting.
DELETE now sets the removal fields; a new POST .../restore clears
them. Active list reads (summary, detail, check toggle) filter to
RemovedAt IS NULL. Frontend surfaces an Undo toast on remove and
handles a new ItemRestored SignalR event.

src/frontend/src/routes/lists/[id]/+page.svelte

@@ -4,6 +4,7 @@
 	import { goto } from '$app/navigation';
 	import { api } from '$lib/api';
 	import { startConnection, stopConnection } from '$lib/signalr';
+	import { toast } from '$lib/toast.svelte';
 	import type { HubConnection } from '@microsoft/signalr';
 
 	interface ListItem {
@@ -70,6 +71,22 @@
 			items = items.filter((i) => i.id !== data.id);
 		});
 
+		connection.on(
+			'ItemRestored',
+			(data: {
+				id: number;
+				name: string;
+				isChecked: boolean;
+				checkedByUserName: string | null;
+				sortOrder: number;
+				recipeTitle: string | null;
+			}) => {
+				if (!items.find((i) => i.id === data.id)) {
+					items = [...items, data];
+				}
+			}
+		);
+
 		connection.on('ListUpdated', (data: { id: number; name: string; storeId: number }) => {
 			if (list) list = { ...list, name: data.name };
 		});
@@ -98,8 +115,17 @@
 		await api(`/api/lists/${listId}/items/${itemId}/check`, { method: 'PATCH' });
 	}
 
-	async function removeItem(itemId: number) {
+	async function removeItem(itemId: number, itemName: string) {
 		await api(`/api/lists/${listId}/items/${itemId}`, { method: 'DELETE' });
+		toast.info(`Removed "${itemName}"`, {
+			duration: 5000,
+			action: {
+				label: 'Undo',
+				onClick: async () => {
+					await api(`/api/lists/${listId}/items/${itemId}/restore`, { method: 'POST' });
+				}
+			}
+		});
 	}
 
 	async function archiveList() {
@@ -157,7 +183,7 @@
 							{/if}
 						</div>
 						<button
-							onclick={() => removeItem(item.id)}
+							onclick={() => removeItem(item.id, item.name)}
 							class="shrink-0 p-1 text-gray-300 active:text-danger"
 							aria-label="Remove {item.name}"
 						>
@@ -192,7 +218,7 @@
 								{/if}
 							</div>
 							<button
-								onclick={() => removeItem(item.id)}
+								onclick={() => removeItem(item.id, item.name)}
 								class="shrink-0 p-1 text-gray-300 active:text-danger"
 								aria-label="Remove {item.name}"
 							>