Feat: 新增下雪特效，加强烟花/下雨在浅色背景的显色（发光粒子+深色雨线）

resources/views/chat/frame.blade.php

@@ -94,11 +94,12 @@
     {{-- ═══════════ 聊天室交互脚本（独立文件维护） ═══════════ --}}
     @include('chat.partials.user-actions')
 
-    {{-- 全屏特效系统：管理员烟花/下雨/雷电 --}}
+    {{-- 全屏特效系统：管理员烟花/下雨/雷电/下雪 --}}
     <script src="/js/effects/effect-manager.js"></script>
     <script src="/js/effects/fireworks.js"></script>
     <script src="/js/effects/rain.js"></script>
     <script src="/js/effects/lightning.js"></script>
+    <script src="/js/effects/snow.js"></script>
 
     @include('chat.partials.scripts')
 

resources/views/chat/partials/input-bar.blade.php

@@ -87,6 +87,9 @@
                 <button type="button" onclick="triggerEffect('lightning')" title="全屏雷电"
                     style="font-size: 11px; padding: 1px 6px; background: #7c3aed; color: #fff; border: none; border-radius: 2px; cursor: pointer;">⚡
                     雷电</button>
+                <button type="button" onclick="triggerEffect('snow')" title="全屏下雪"
+                    style="font-size: 11px; padding: 1px 6px; background: #0891b2; color: #fff; border: none; border-radius: 2px; cursor: pointer;">❄️
+                    下雪</button>
             @endif
 
             <button type="button" onclick="location.reload()"