fix(mobile): 44px touch targets for primary call/thread/mod controls (P1)

Deep-audit follow-up. New shared MobileTouchTarget class (@media <=750px ->
minWidth/minHeight 44px) applied via className to the primary interactive
controls folds renders below 44px:
- in-call control bar (7 buttons) + persistent call-status bar (4 buttons)
- thread "N replies" chip
- knock Approve/Deny buttons
- server-ACL entry remove button

folds size variants set only padding (no width/height/min-*), so the class
raises the hit-area floor to 44px with the icon/label staying centered at its
normal size; desktop is untouched (@media-gated). Verified by two review passes
(no distortion, no layout overflow, counts exact).

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

src/app/features/call/Controls.tsx

@@ -2,6 +2,7 @@ import React from 'react';
 import { Icon, IconButton, Icons, Line, Text, Tooltip, TooltipProvider } from 'folds';
 import { useAtom } from 'jotai';
 import * as css from './styles.css';
+import { MobileTouchTarget } from '../../styles/mobile.css';
 import { callChatAtom } from '../../state/callEmbed';
 import { AsyncStatus, useAsyncCallback } from '../../hooks/useAsyncCallback';
 
@@ -36,6 +37,7 @@ export function MicrophoneButton({ enabled, onToggle }: MicrophoneButtonProps) {
           fill="Soft"
           radii="400"
           size="400"
+          className={MobileTouchTarget}
           onClick={toggleMic}
           aria-label={enabled ? 'Turn Off Microphone' : 'Turn On Microphone'}
           outlined
@@ -70,6 +72,7 @@ export function SoundButton({ enabled, onToggle }: SoundButtonProps) {
           fill="Soft"
           radii="400"
           size="400"
+          className={MobileTouchTarget}
           onClick={() => onToggle()}
           aria-label={enabled ? 'Undeafen' : 'Deafen'}
           outlined
@@ -113,6 +116,7 @@ export function VideoButton({ enabled, onToggle, disabled }: VideoButtonProps) {
           fill="Soft"
           radii="400"
           size="400"
+          className={MobileTouchTarget}
           onClick={toggleVideo}
           outlined
           disabled={disabled || loading}
@@ -155,6 +159,7 @@ export function ScreenShareButton({ enabled, onToggle }: ScreenShareButtonProps)
           fill="Soft"
           radii="400"
           size="400"
+          className={MobileTouchTarget}
           onClick={() => onToggle()}
           aria-label={enabled ? 'Stop Screenshare' : 'Start Screenshare'}
           outlined
@@ -200,6 +205,7 @@ export function FullscreenButton({ isFullscreen, onToggle }: FullscreenButtonPro
           fill="Soft"
           radii="400"
           size="400"
+          className={MobileTouchTarget}
           onClick={onToggle}
           aria-label={isFullscreen ? 'Exit Fullscreen' : 'Fullscreen'}
           aria-pressed={isFullscreen}
@@ -234,6 +240,7 @@ export function ScreenshareAudioButton({ muted, onToggle }: ScreenshareAudioButt
           fill="Soft"
           radii="400"
           size="400"
+          className={MobileTouchTarget}
           onClick={onToggle}
           aria-label={muted ? 'Unmute Screenshare Audio' : 'Mute Screenshare Audio'}
           aria-pressed={muted}
@@ -266,6 +273,7 @@ export function ChatButton() {
           fill="Soft"
           radii="400"
           size="400"
+          className={MobileTouchTarget}
           onClick={() => setChat(!chat)}
           aria-label={chat ? 'Close Chat' : 'Open Chat'}
           aria-pressed={chat}