Add seasonal effects for Pi Day, Pride, Rain, and Storm; enhance existing styles

- Introduced new CSS and JS files for Pi Day, Pride, Rain, and Storm effects.
- Updated existing seasonal styles (e.g., Halloween, Hearts, Resurrection) to improve performance with 'contain: layout paint'.
- Enhanced animations for seasonal effects, including adjustments to keyframes and element creation logic.
- Added configuration options for new effects in the main seasonals.js file.
- Updated test-site.html to include new seasonal options in the dropdown.

Jellyfin.Plugin.Seasonals/Web/rain.js

@@ -0,0 +1,77 @@
+// 1. Read Configuration
+const config = window.SeasonalsPluginConfig?.Rain || {};
+
+const enabled = config.EnableRain !== undefined ? config.EnableRain : true;
+const isMobile = window.innerWidth <= 768;
+const elementCount = isMobile ? (config.RaindropCountMobile || 150) : (config.RaindropCount || 300);
+const rainSpeed = config.RainSpeed || 1.0;
+
+let msgPrinted = false;
+
+// 2. Toggle Function
+function toggleRain() {
+  const container = document.querySelector('.rain-container');
+  if (!container) return;
+
+  const videoPlayer = document.querySelector('.videoPlayerContainer');
+  const trailerPlayer = document.querySelector('.youtubePlayerContainer');
+  const isDashboard = document.body.classList.contains('dashboardDocument');
+  const hasUserMenu = document.querySelector('#app-user-menu');
+
+  if (videoPlayer || trailerPlayer || isDashboard || hasUserMenu) {
+    container.style.display = 'none';
+    if (!msgPrinted) {
+      console.log('Rain hidden');
+      msgPrinted = true;
+    }
+  } else {
+    container.style.display = 'block';
+    if (msgPrinted) {
+      console.log('Rain visible');
+      msgPrinted = false;
+    }
+  }
+}
+
+// 3. MutationObserver
+const observer = new MutationObserver(toggleRain);
+observer.observe(document.body, {
+  childList: true,
+  subtree: true,
+  attributes: true
+});
+
+// 4. Element Creation
+function createElements() {
+  const container = document.querySelector('.rain-container') || document.createElement('div');
+
+  if (!document.querySelector('.rain-container')) {
+    container.className = 'rain-container';
+    container.setAttribute('aria-hidden', 'true');
+    document.body.appendChild(container);
+  }
+
+  for (let i = 0; i < elementCount; i++) {
+    const drop = document.createElement('div');
+    drop.className = 'raindrop-pure';
+    
+    drop.style.left = `${Math.random() * 140}vw`;
+    drop.style.top = `${-20 - Math.random() * 50}vh`;
+
+    const duration = (0.5 + Math.random() * 0.5) / (rainSpeed || 1);
+    drop.style.animation = `pure-rain ${duration}s linear infinite`;
+    drop.style.animationDelay = `${Math.random() * 2}s`;
+    drop.style.opacity = Math.random() * 0.5 + 0.3;
+
+    container.appendChild(drop);
+  }
+}
+
+// 5. Initialization
+function initializeRain() {
+  if (!enabled) return;
+  createElements();
+  toggleRain();
+}
+
+initializeRain();