fix(skins): keep menu links visible and align native select look

The wrapper had width:100% which pushed the right-side menu links
(mail/contacts/settings/logout) out of #taskbar in Classic, and the
global custom select styling defeated Roundcube's native select
rendering — even when reset — because any background-image on a
<select> disables the native gradient/rounded corners.

- Scope the custom appearance/SVG-chevron CSS to Elastic and Larry
- Add a Classic-specific rule (width:auto, max-width, -2px nudge) that
  preserves Roundcube's native select look in #taskbar
- Drop the inline padding:0 imposed by the PHP renderer; let CSS own it
- Cap the Larry wrapper width to keep .button-logout in flow, and move
  the Larry-only styling out of the JS into the scoped CSS rule

Fixes #1

ident_switch.php

@@ -222,7 +222,7 @@ class ident_switch extends rcube_plugin
 
         $select = new html_select([
             'id' => 'plugin-ident_switch-account',
-            'style' => 'display: none; padding: 0;',
+            'style' => 'display: none;',
             'onchange' => 'plugin_switchIdent_switch(this.value);',
         ]);
         $select->add($accNames, $accValues);