fix(settings): restore background swatch grid layout; verify N4 poll fix

- Add grow="Yes" to ChatBgGrid and SeasonalBgGrid containers so they
  expand to fill their flex parent — without it the Box shrank to one
  column (~76px wide) because folds Box defaults to display:flex and
  the wrapper is a flex-row with no explicit width.
- Mark N4 (PollContent) FIXED ✅ VERIFIED in LOTUS_BUGS.md after
  confirmed pass on default Cinny themes and Lotus TDS.
- Mark B1 and B4 PASS in LOTUS_TESTING.md.

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

src/app/features/settings/general/General.tsx

@@ -1668,6 +1668,7 @@ function SeasonalBgGrid({
 }) {
   return (
     <Box
+      grow="Yes"
       style={{
         display: 'grid',
         gridTemplateColumns: `repeat(auto-fill, minmax(${toRem(76)}, 1fr))`,
@@ -1734,6 +1735,7 @@ function ChatBgGrid() {
 
   return (
     <Box
+      grow="Yes"
       style={{
         display: 'grid',
         gridTemplateColumns: `repeat(auto-fill, minmax(${toRem(76)}, 1fr))`,