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/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',
         }}