feat(ui): add delete button to RecipeSheet + fix NaNd ago + full QueueItem in POST response

- RecipeSheet: add onDelete prop and 'Remove from queue' button at bottom of sheet
- +page.svelte: wire onDelete -> removeItem in RecipeSheet
- POST /api/queue: return full QueueItem (with createdAt, phases) instead of stripped subset
- TimelineRow: defensive relTime() handles undefined/NaN, uses createdAt ?? enqueuedAt

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/routes/+page.svelte

@@ -352,6 +352,7 @@
 			item={selectedItem}
 			onClose={() => (selectedItem = null)}
 			onRetry={(id) => { retryItem(id); selectedItem = null; }}
+			onDelete={(id) => { removeItem(id); selectedItem = null; }}
 		/>
 	{/if}
 </div>