Fix logout button symbol for Android browser compatibility

- Replace power symbol (⏻) with north-east arrow (↗) for logout button
- Resolves display issue where Android browsers show "x" instead of symbol
- Arrow symbol is more universally supported across platforms
- Maintains tooltip for clarity and accessibility
- Symbol represents "exit" or "logout" concept effectively

🤖 Generated with [Claude Code](https://claude.ai/code)

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

public/playlist.html

@@ -487,7 +487,7 @@
                     </div>
                     <div class="filter-right">
                         <button class="nav-btn" onclick="goBack()" title="Back">◀</button>
-                        <button class="nav-btn" onclick="logout()" title="Logout">⏻</button>
+                        <button class="nav-btn" onclick="logout()" title="Logout">↗</button>
                     </div>
                 </div>
             </div>