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/features/room/ScheduledMessagesTray.tsx

@@ -1,6 +1,6 @@
 import React, { useCallback, useEffect, useMemo, useState } from 'react';
 import { useAtom } from 'jotai';
-import { Box, Icon, IconButton, Icons, Text, color, config } from 'folds';
+import { Box, Button, Icon, IconButton, Icons, Text, color, config } from 'folds';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { scheduledMessagesAtom, ScheduledMessage } from '../../state/scheduledMessages';
 import { cancelScheduledMessage } from '../../utils/scheduledMessages';
@@ -106,24 +106,24 @@ export function ScheduledMessagesTray({ roomId }: ScheduledMessagesTrayProps) {
       }}
     >
       {/* Tray header */}
-      <Box
-        alignItems="Center"
-        gap="200"
-        style={{
-          padding: `${config.space.S100} ${config.space.S300}`,
-          cursor: 'pointer',
-        }}
+      <Button
+        variant="Secondary"
+        fill="None"
+        radii="0"
         onClick={() => setExpanded((v) => !v)}
-        as="button"
         aria-expanded={expanded}
         aria-label={`${messages.length} scheduled message${messages.length !== 1 ? 's' : ''}`}
+        before={<Icon src={Icons.Clock} size="50" />}
+        after={<Icon src={expanded ? Icons.ChevronTop : Icons.ChevronBottom} size="50" />}
+        style={{
+          padding: `${config.space.S100} ${config.space.S300}`,
+          justifyContent: 'flex-start',
+        }}
       >
-        <Icon src={Icons.Clock} size="50" />
-        <Text size="T200" style={{ flex: 1, fontWeight: 600 }}>
+        <Text size="T200" style={{ flex: 1, fontWeight: 600, textAlign: 'left' }}>
           {messages.length} scheduled message{messages.length !== 1 ? 's' : ''}
         </Text>
-        <Icon src={expanded ? Icons.ChevronTop : Icons.ChevronBottom} size="50" />
-      </Box>
+      </Button>
 
       {/* Tray items */}
       {expanded && (