feat(call): add sound effects and incoming call notification UI

- Implemented sound management for call events including mute, unmute, deafen, undeafen, call joined, call depart, and dialing sounds.
- Created a new CallSounds class to handle sound playback and state management.
- Added IncomingCallNotification component to display incoming call alerts with caller information and action buttons.
- Styled the incoming call notification using vanilla-extract CSS for animations and layout.
- Integrated sound playback for incoming calls with a 15-second threshold for dialing sound.

src/index.css

@@ -1,3 +1,4 @@
+/* Twemoji font (Twitter emoji) */
 @font-face {
   font-family: Twemoji;
   src: url('../public/font/Twemoji.Mozilla.v15.1.0.woff2'),
@@ -5,6 +6,28 @@
   font-display: swap;
 }
 
+/* Apple Color Emoji - uses local Apple Color Emoji if available (macOS/iOS),
+   falls back to Segoe UI Emoji (Windows) or Noto (Linux/Android) */
+@font-face {
+  font-family: AppleColorEmoji;
+  src: local('Apple Color Emoji'),
+    local('Segoe UI Emoji'),
+    local('Noto Color Emoji');
+  font-display: swap;
+}
+
+/* System emoji - uses native OS emoji */
+@font-face {
+  font-family: SystemEmoji;
+  src: local('Apple Color Emoji'),
+    local('Segoe UI Emoji'),
+    local('Segoe UI Symbol'),
+    local('Noto Color Emoji'),
+    local('Android Emoji'),
+    local('EmojiOne Color');
+  font-display: swap;
+}
+
 :root {
   --tc-link: hsl(213deg 100% 45%);
 
@@ -18,7 +41,7 @@
   --mx-uc-7: hsl(242, 100%, 45%);
   --mx-uc-8: hsl(94, 100%, 35%);
 
-  --font-emoji: 'Twemoji_DISABLED';
+  --font-emoji: 'AppleColorEmoji';
   --font-secondary: 'InterVariable', var(--font-emoji), sans-serif;
 }