feat: add splash screen with logo on app load and after login

- Show sofarr logo splash screen while app initialises
- On page load: splash stays visible while checking auth and fetching data
- After login: splash reappears while fetching initial downloads
- Minimum 1.2s display with smooth fade-out transition
- Subtle pulse animation on the logo

public/app.js

@@ -4,6 +4,7 @@ let refreshInterval = null;
 let currentRefreshRate = 5000; // default 5 seconds
 let isAdmin = false;
 let showAll = false;
+const SPLASH_MIN_MS = 1200; // minimum splash display time
 
 // Apply saved theme immediately (before DOMContentLoaded to avoid flash)
 (function() {
@@ -63,7 +64,30 @@ function stopAutoRefresh() {
   }
 }
 
+function showSplash() {
+  const splash = document.getElementById('splash-screen');
+  splash.style.display = 'flex';
+  splash.style.opacity = '1';
+  splash.classList.remove('fade-out');
+}
+
+function dismissSplash(startTime) {
+  return new Promise(resolve => {
+    const elapsed = Date.now() - (startTime || 0);
+    const remaining = Math.max(0, SPLASH_MIN_MS - elapsed);
+    setTimeout(() => {
+      const splash = document.getElementById('splash-screen');
+      splash.classList.add('fade-out');
+      splash.addEventListener('transitionend', () => {
+        splash.style.display = 'none';
+        resolve();
+      }, { once: true });
+    }, remaining);
+  });
+}
+
 async function checkAuthentication() {
+  const splashStart = Date.now();
   try {
     const response = await fetch('/api/auth/me');
     const data = await response.json();
@@ -72,13 +96,16 @@ async function checkAuthentication() {
       currentUser = data.user;
       isAdmin = !!data.user.isAdmin;
       showDashboard();
-      fetchUserDownloads(true);
+      await fetchUserDownloads(true);
       startAutoRefresh();
+      await dismissSplash(splashStart);
     } else {
+      await dismissSplash(splashStart);
       showLogin();
     }
   } catch (err) {
     console.error('Authentication check failed:', err);
+    await dismissSplash(splashStart);
     showLogin();
   }
 }
@@ -103,9 +130,12 @@ async function handleLogin(e) {
     if (data.success) {
       currentUser = data.user;
       isAdmin = !!data.user.isAdmin;
+      showSplash();
       showDashboard();
-      fetchUserDownloads(true);
+      const splashStart = Date.now();
+      await fetchUserDownloads(true);
       startAutoRefresh();
+      await dismissSplash(splashStart);
     } else {
       showLoginError(data.error || 'Login failed');
     }