fix: settings dropdowns, background animations, ringing, avatar decorations

Settings dropdowns (Bug #3):
- Add reusable SettingsSelect component using Menu+PopOut+FocusTrap — exact
  same pattern as Message Layout, so all dropdowns look consistent
- Replace raw <select> for Seasonal Theme, UI Font, AFK Timeout, and
  Join & Leave Sounds with SettingsSelect

Animated chat backgrounds bleeding onto content (Bug #6 / #7):
- Remove filter:brightness() and opacity animations from chatBackground.ts
  (animRainGlowKeyframe, animGridBrightnessKeyframe, animFirefliesGlowKeyframe,
  animFirefliesBlinkKeyframe). These were applied to the Page element which
  caused ALL descendants (messages, composer) to flash in sync.
  Also created a CSS stacking context on Page that pushed SeasonalEffect
  (position:fixed; z-index:9997) behind the animated background layer.
- Only backgroundPosition / backgroundSize animations remain — safe, do not
  affect descendants, and do not create stacking contexts.
- Remove now-unused animation keyframe imports from chatBackground.ts.

Voice ringing in persistent rooms (Bug #5):
- Narrow the ringing condition from (Invite|Knock|Restricted) to only Invite,
  matching exactly the rooms where the call button is visible.
- Add room.isCallRoom() early-exit so m.join_rule:call rooms never ring.

Avatar decoration images not loading (Bug #8):
- Change loading="lazy" → loading="eager" in DecorationPreviewCell.
  Lazy loading does not reliably trigger for images inside nested overflow
  scroll containers (the settings panel scroll area), so images never loaded.

Docs: LOTUS_BUGS.md updated with root cause and resolution for all 5 new bugs.
Docs: LOTUS_TODO.md adds P5-35/P5-36 (deferred desktop notification/jump list).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/features/settings/account/ProfileDecoration.tsx

@@ -60,7 +60,7 @@ function DecorationPreviewCell({
       <img
         src={`${DECORATION_CDN}/${slug}.png`}
         alt={name}
-        loading="lazy"
+        loading="eager"
         decoding="async"
         style={{
           position: 'absolute',