fix(ui): replace ungated invented CSS vars with folds tokens (native-cinny audit 1/N)

Audit of our delta vs Cinny v4.12.3 found invented CSS vars (--tc-*, --bg-*)
used outside Lotus-Terminal-gated code, which render unstyled/wrong on stock
themes. Batch 1:
- MemberVerificationBadge: --tc-positive/warning-normal -> color.Success/Warning.Main
- RoomInput (gif/location errors): --tc-danger-normal -> color.Critical.Main
- MsgTypeRenderers (location iframe): --bg-surface-border -> color.SurfaceVariant.ContainerLine
- MessageSearch (cached-room row): --bg-surface-variant -> color.SurfaceVariant.Container
- PrescreenControls (mic-denied): --tc-critical-high -> color.Critical.Main

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

src/app/components/MemberVerificationBadge.tsx

@@ -1,5 +1,5 @@
 import React from 'react';
-import { Icon, Icons, Text, Tooltip, TooltipProvider } from 'folds';
+import { color, Icon, Icons, Text, Tooltip, TooltipProvider } from 'folds';
 import { useUserVerifiedStatus } from '../hooks/useUserVerifiedStatus';
 
 type MemberVerificationBadgeProps = {
@@ -9,8 +9,7 @@ type MemberVerificationBadgeProps = {
 export function MemberVerificationBadge({ userId }: MemberVerificationBadgeProps) {
   const vs = useUserVerifiedStatus(userId);
   if (vs === 'unknown') return null;
-  const color =
-    vs === 'verified' ? 'var(--tc-positive-normal, #5effc4)' : 'var(--tc-warning-normal, #ffcc55)';
+  const iconColor = vs === 'verified' ? color.Success.Main : color.Warning.Main;
   const label = vs === 'verified' ? 'Identity verified' : 'Not verified';
   return (
     <TooltipProvider
@@ -27,7 +26,7 @@ export function MemberVerificationBadge({ userId }: MemberVerificationBadgeProps
           title={label}
           style={{ display: 'inline-flex', alignItems: 'center', flexShrink: 0 }}
         >
-          <Icon size="100" src={Icons.ShieldUser} style={{ color }} />
+          <Icon size="100" src={Icons.ShieldUser} style={{ color: iconColor }} />
         </span>
       )}
     </TooltipProvider>

src/app/components/message/MsgTypeRenderers.tsx

@@ -529,7 +529,7 @@ export function MLocation({ content }: MLocationProps) {
         style={{
           width: '280px',
           height: '160px',
-          border: '1px solid var(--bg-surface-border)',
+          border: `${config.borderWidth.B300} solid ${color.SurfaceVariant.ContainerLine}`,
           borderRadius: '8px',
           display: 'block',
         }}