feat(tasks): snooze — park a task at the bottom until a time

Snooze puts a task out of the way without finishing it or filing it: it sinks to
the bottom of its list and greys, and comes back on its own when its time passes.
No job wakes it — "snoozed" is just snoozed_until being still in the future, read
against the clock each time the list is ordered.

- `snoozed_until` on tasks (migration 0031); the list order sinks a still-snoozed
  task below everything, and it rejoins its place the moment the time passes.
- POST /tasks/{id}/snooze {until} — an RFC3339 time to snooze to, or empty to wake.
  Nothing else about the task moves; a snooze is about when you want to see it, not
  when it is due.
- The task drawer gains quick picks (this evening / tomorrow / next week) and a
  custom time, and a Wake now once it is snoozed. The row dims and carries a
  "snoozed until X" mark, and the list keeps snoozed tasks at the foot — the client
  sorts the same way the server does, so a drag-sorted list does not jump on reload.

Tests: snooze sinks a task below one made after it and waking returns it (Go); and
from the drawer the row greys, shows the mark, and un-greys on wake (e2e). Full
suites green.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web/src/lib/components/TaskList.svelte

@@ -120,7 +120,18 @@
 		}
 	}
 
-	let ordered = $derived([...tasks].sort((a, b) => a.sort_order - b.sort_order));
+	// A snoozed task sinks below the rest, then rises back when its time passes —
+	// the same order the server sorts a list in, kept here so a drag-sorted list
+	// agrees rather than jumping when it reloads.
+	const snoozedNow = (t) => t.snoozed_until && new Date(t.snoozed_until) > new Date();
+	let ordered = $derived(
+		[...tasks].sort((a, b) => {
+			const sa = snoozedNow(a) ? 1 : 0;
+			const sb = snoozedNow(b) ? 1 : 0;
+			if (sa !== sb) return sa - sb;
+			return a.sort_order - b.sort_order;
+		})
+	);
 </script>
 
 {#each ordered as task (task.id)}