fix: remove blue tap highlight and focus ring globally in WebView

-webkit-tap-highlight-color was only on 2 specific elements; every
div/song-item/card still showed a blue flash on tap in Android WebView.
*:focus{outline:none} replaces the button-only rule and covers clickable
divs as well.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

styles.css

@@ -12,7 +12,8 @@
   --player-h:112px;--sidebar-w:240px;
   --font:'Outfit',sans-serif;--mono:'JetBrains Mono',monospace;
 }
-*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
+*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;-webkit-tap-highlight-color:transparent}
+*:focus{outline:none}
 html,body{height:100%;font-family:var(--font);background:var(--bg);color:var(--text);overflow:hidden}
 ::-webkit-scrollbar{width:4px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--surface2);border-radius:2px}