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-status/CallControl.tsx

@@ -5,6 +5,7 @@ import { StatusDivider } from './components';
 import { CallEmbed, useCallControlState } from '../../plugins/call';
 import { AsyncStatus, useAsyncCallback } from '../../hooks/useAsyncCallback';
 import { callEmbedAtom } from '../../state/callEmbed';
+import { MobileTouchTarget } from '../../styles/mobile.css';
 
 type MicrophoneButtonProps = {
   enabled: boolean;
@@ -31,6 +32,7 @@ function MicrophoneButton({ enabled, onToggle, disabled }: MicrophoneButtonProps
           fill="Soft"
           radii="300"
           size="300"
+          className={MobileTouchTarget}
           onClick={toggleMic}
           outlined
           disabled={disabled || loading}
@@ -66,6 +68,7 @@ function SoundButton({ enabled, onToggle, disabled }: SoundButtonProps) {
           fill="Soft"
           radii="300"
           size="300"
+          className={MobileTouchTarget}
           onClick={() => onToggle()}
           aria-label={enabled ? 'Deafen' : 'Undeafen'}
           aria-pressed={enabled}
@@ -108,6 +111,7 @@ function VideoButton({ enabled, onToggle, disabled }: VideoButtonProps) {
           fill="Soft"
           radii="300"
           size="300"
+          className={MobileTouchTarget}
           onClick={toggleVideo}
           aria-label={enabled ? 'Stop Video' : 'Start Video'}
           aria-pressed={enabled}
@@ -147,6 +151,7 @@ function ScreenShareButton({ enabled, onToggle, disabled }: ScreenShareButtonPro
           fill="Soft"
           radii="300"
           size="300"
+          className={MobileTouchTarget}
           onClick={onToggle}
           aria-label={enabled ? 'Stop Screenshare' : 'Start Screenshare'}
           aria-pressed={enabled}