fix(ui): settings modal sizing regression + 17 more folds audit findings

Fix settings modal regression: Modal500 was wrapped in useModalStyle(560),
forcing maxWidth 560px and squishing the two-pane Settings layout (folds
size="500" is ~50rem). Restore desktop width to the folds recipe while
keeping mobile fullscreen.

N-series fixes:
- N13 ScheduledMessagesTray header: <Box as="button"> -> folds <Button>
- N28 composer char counter: drop undefined --tc-surface-low + opacity,
  use priority="300" and config.space token
- N31 collapsible "Read more" toggle: padded <Button> -> flush inline-button
  pattern matching (edited) link
- N41 UserPrivateNotes "Saving..." now shows a folds <Spinner>
- N43 Night Light slider: add accentColor; label opacity -> priority
- N44 mention-highlight Reset: bare <button> -> folds <Button> (drops
  undefined --border-interactive-normal); Boot button kept (TDS-only)
- N45 SelectTheme trigger variant -> Secondary to match SettingsSelect
- N49 RoomInsights StatTile emoji -> folds <Icon> (Photo/VideoCamera/
  Headphone/File)
- N54/N57 PiP overlay badges + fullscreen button: token discipline
  (config.radii/space, folds Text); dark scrim kept for video legibility
- N60 knock badge: match Pinned Messages pattern (no wrapper div, toRem
  insets, no hardcoded size overrides)
- N62 unverified-device banner: 3px left-accent -> standard border via
  color.Warning.ContainerLine; drop opacity hacks
- N65 Edit History: real "Load more" pagination (accumulate next_batch,
  de-dupe by id, re-sort by ts) replacing passive text
- N66 search date fields: raw <input type="date"> -> folds <Input>
- N67 SeasonalEffect z-index 9999 -> 9997 (below Night Light + modals)
- N73 Pending Requests header uses css.MembersGroupLabel
- N74 remove raw em-sized emoji <span> in RoomNavItem name
- N85/N86 RemindMeDialog: <Box role="dialog"> -> folds <Dialog>; preset
  MenuItems -> Buttons (fixes invalid menuitem-in-dialog ARIA)

Document deliberate WON'T FIX rationale for N9, N51, N61, N71, N75, N77.

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

src/app/components/user-profile/UserRoomProfile.tsx

@@ -237,11 +237,20 @@ function UserPrivateNotes({ userId }: { userId: string }) {
 
   return (
     <Box direction="Column" gap="200">
-      <Box justifyContent="SpaceBetween" alignItems="Center">
+      <Box justifyContent="SpaceBetween" alignItems="Center" gap="200">
         <Text size="L400">Private Note</Text>
-        <Text size="T200" priority="400">
-          {saving ? 'Saving…' : charsLeft < 100 ? `${charsLeft} left` : ''}
-        </Text>
+        {saving ? (
+          <Box alignItems="Center" gap="100" shrink="No">
+            <Spinner variant="Success" fill="Solid" size="100" />
+            <Text size="T200" priority="400">
+              Saving…
+            </Text>
+          </Box>
+        ) : (
+          <Text size="T200" priority="400">
+            {charsLeft < 100 ? `${charsLeft} left` : ''}
+          </Text>
+        )}
       </Box>
       <textarea
         value={draft}