feat: revise login screen with logo and smooth transition to splash

- Replace 'Login to Emby' heading with sofarr logo and subtitle
- Subtitle reads 'Login with your Emby credentials'
- Login form fades out smoothly before splash screen appears
- Form labels remain left-aligned within centered login box

public/app.js

@@ -64,6 +64,18 @@ function stopAutoRefresh() {
   }
 }
 
+function fadeOutLogin() {
+  return new Promise(resolve => {
+    const login = document.getElementById('login-container');
+    login.classList.add('fade-out');
+    login.addEventListener('transitionend', () => {
+      login.style.display = 'none';
+      login.classList.remove('fade-out');
+      resolve();
+    }, { once: true });
+  });
+}
+
 function showSplash() {
   const splash = document.getElementById('splash-screen');
   splash.style.display = 'flex';
@@ -130,6 +142,8 @@ async function handleLogin(e) {
     if (data.success) {
       currentUser = data.user;
       isAdmin = !!data.user.isAdmin;
+      // Fade out login, then show splash while loading data
+      await fadeOutLogin();
       showSplash();
       showDashboard();
       const splashStart = Date.now();