feat(status): built-in and custom status presets

The Status Message field required typing every status from scratch. Add
a one-click preset row:

- Built-in "Quick statuses" spanning gaming, social, life and work
  (Gaming, In a party, Ranked grind, AFK, Watching, In a meeting,
  Working remotely, Lunch, On vacation, Out sick...), each carrying a
  suggested auto-clear so a click sets the message and the timer at once.
- Custom presets: save the current status as a reusable preset, stored
  in io.lotus.status_presets account data (synced across devices via the
  shared account-data list store), de-duped by normalized label, capped
  at 20, deletable inline.

The existing save path is factored into a shared applyStatus() used by
the Save button and by preset apply, so server writes, the status
localStorage keys, and the auto-clear expiry bookkeeping stay identical.
Ordering/de-dupe logic is pure in utils/statusPresets.ts (upsertPreset,
normalizeLabel) with unit tests; no change to the presence wire format,
expiry monitor, or presence-mode selector.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/hooks/useStatusPresets.ts

@@ -0,0 +1,43 @@
+import { useCallback } from 'react';
+import { useMatrixClient } from './useMatrixClient';
+import { createAccountDataListStore } from './createAccountDataListStore';
+import { StatusPreset, upsertPreset } from '../utils/statusPresets';
+
+const STATUS_PRESETS_KEY = 'io.lotus.status_presets';
+const MAX_PRESETS = 20;
+
+type StatusPresetsContent = {
+  presets: StatusPreset[];
+};
+
+// Shared, concurrency-safe store. See createAccountDataListStore for why the
+// snapshot + write queue must be module-scoped (writes are serialized to avoid
+// lost updates, since setAccountData replaces the whole content with no merge).
+const statusPresetsStore = createAccountDataListStore<StatusPreset[], StatusPresetsContent>({
+  eventType: STATUS_PRESETS_KEY,
+  read: (content) => content?.presets ?? [],
+  write: (presets) => ({ presets }),
+});
+
+export function useStatusPresets(): {
+  presets: StatusPreset[];
+  addPreset: (preset: StatusPreset) => Promise<void>;
+  removePreset: (id: string) => Promise<void>;
+} {
+  const mx = useMatrixClient();
+  const presets = statusPresetsStore.useValue(mx);
+
+  const addPreset = useCallback(
+    (preset: StatusPreset) =>
+      statusPresetsStore.enqueueWrite(mx, (current) => upsertPreset(current, preset, MAX_PRESETS)),
+    [mx],
+  );
+
+  const removePreset = useCallback(
+    (id: string) =>
+      statusPresetsStore.enqueueWrite(mx, (current) => current.filter((p) => p.id !== id)),
+    [mx],
+  );
+
+  return { presets, addPreset, removePreset };
+}