fix(wave-3): audit fixes — ACL guards, presence, moderation, theming perf

Wave-3 bug-hunt fixes (findings in LOTUS_TODO), reviewed + gate-green:
- 🔴 ACL editor [H1–H4]: block saving an empty allow-list (was a one-click
  federation brick), warn on self-ban (case-insensitive glob match of
  mx.getDomain() vs allow/deny), accept real globs (1.2.3.*, *.evil.*), and
  gate Save behind a confirm dialog.
- 🔴 [P1] room context menu no longer acts on the wrong room after a live
  reorder (key by roomId, not list index). 🔴 [P2] status writes no longer
  force presence to online over Invisible/DND (shared presenceStateFromSetting).
- 🟠 [P3] timed mutes restored on boot; [P4] custom-status auto-clear now fires
  (always-mounted StatusExpiryMonitor); [P5] timezone also PUT to the m.tz
  profile field so it's visible to others; [H6] RoomInsights single-pass
  min/max (was Math.min(...spread) stack overflow); [H7/H8] mod-log labels.
- 🟡 [P6/P7] favorites collapse+filter, [P8] charCount reset, [P9] DM preview
  refresh on decrypt; theming [T-P1] lazy decorations, [T-P2] drop the redundant
  always-on body animation, [T-P4] live useReducedMotion, [T-P5] decoration key.
- NATIVE-CINNY LAW: notification presets + Powers permissions use folds icons.

DEFERRED: [H5] invite-QR is fetched from api.qrserver.com (third-party leak);
local generation needs a bundled QR lib (not added). tsc/eslint/prettier clean,
build OK, 677 tests.

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

src/app/hooks/useReducedMotion.ts

@@ -0,0 +1,34 @@
+import { useEffect, useState } from 'react';
+
+const REDUCED_MOTION_QUERY = '(prefers-reduced-motion: reduce)';
+
+const readReducedMotion = (): boolean =>
+  typeof window !== 'undefined' &&
+  typeof window.matchMedia === 'function' &&
+  window.matchMedia(REDUCED_MOTION_QUERY).matches;
+
+/**
+ * Reactively tracks the OS `prefers-reduced-motion: reduce` setting.
+ *
+ * Unlike a one-off `window.matchMedia(...).matches` read, this subscribes to the
+ * media query's `change` event, so toggling the OS setting mid-session updates
+ * the returned value (and any animation gated on it) without a page reload.
+ * SSR/undefined-safe: returns `false` when `window`/`matchMedia` is unavailable.
+ */
+export function useReducedMotion(): boolean {
+  const [reduced, setReduced] = useState<boolean>(readReducedMotion);
+
+  useEffect(() => {
+    if (typeof window === 'undefined' || typeof window.matchMedia !== 'function') {
+      return undefined;
+    }
+    const mql = window.matchMedia(REDUCED_MOTION_QUERY);
+    const onChange = (event: MediaQueryListEvent) => setReduced(event.matches);
+    // Re-sync in case the setting changed between the initial render and this effect.
+    setReduced(mql.matches);
+    mql.addEventListener('change', onChange);
+    return () => mql.removeEventListener('change', onChange);
+  }, []);
+
+  return reduced;
+}