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/message/MsgTypeRenderers.tsx

@@ -1,5 +1,5 @@
 import React, { CSSProperties, ReactNode, useEffect, useRef, useState } from 'react';
-import { Box, Button, Icon, Icons, Text, color, toRem } from 'folds';
+import { Box, Button, config, Icon, Icons, Text, color, toRem } from 'folds';
 import { IContent } from 'matrix-js-sdk';
 import { JUMBO_EMOJI_REG, URL_REG } from '../../utils/regex';
 import { trimReplyFromBody } from '../../utils/room';
@@ -94,15 +94,21 @@ function CollapsibleBody({ eventId, children }: CollapsibleBodyProps) {
         )}
       </div>
       {needsCollapse && (
-        <Button
-          size="300"
-          variant="Secondary"
-          fill="None"
-          style={{ marginTop: '4px' }}
+        <button
+          type="button"
           onClick={() => setCollapsed((c) => !c)}
+          style={{
+            cursor: 'pointer',
+            background: 'none',
+            border: 'none',
+            padding: 0,
+            marginTop: config.space.S100,
+          }}
         >
-          <Text size="B300">{collapsed ? 'Read more ↓' : 'Show less ↑'}</Text>
-        </Button>
+          <Text as="span" size="T200" style={{ color: color.Primary.Main }}>
+            {collapsed ? 'Read more ↓' : 'Show less ↑'}
+          </Text>
+        </button>
       )}
     </div>
   );