fix(call): deafen button aria-label was inverted relative to its tooltip

`enabled` means sound is on; the tooltip said "Deafen" but the aria-label
said "Undeafen". Align the label with the tooltip and add aria-pressed to
match the call-status bar's equivalent button.

Fixes #33

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/call/Controls.tsx

@@ -74,7 +74,8 @@ export function SoundButton({ enabled, onToggle }: SoundButtonProps) {
           size="400"
           className={MobileTouchTarget}
           onClick={() => onToggle()}
-          aria-label={enabled ? 'Undeafen' : 'Deafen'}
+          aria-label={enabled ? 'Deafen' : 'Undeafen'}
+          aria-pressed={enabled}
           outlined
         >
           <Icon