feat: Add weather foreground option (experimental)

- Add weatherEffectsForeground setting to render weather effects in front of chat
- Add UI toggle in main panel (visible when Dynamic Weather toggle is visible)
- Apply z-index 9998 when foreground option is enabled
- Fix weather container sizing with viewport units (100vh/100dvh) for better mobile support

style.css

@@ -9428,8 +9428,9 @@ body[data-theme="cyberpunk"] .rpg-music-widget-play {
     position: fixed;
     top: 0;
     left: 0;
-    width: 100%;
-    height: 100%;
+    width: 100vw;
+    height: 100vh;
+    height: 100dvh; /* Dynamic viewport height for mobile browsers */
     pointer-events: none;
     z-index: 1;
     overflow: hidden;