桌面应用图标替换为 B-brackets 设计（深藏青 + 白/蓝花括号）

- icon.svg 取自 opsx-icon-options/api/B-brackets.svg，全套光栅重生成：
  icon.icns（iconutil）、icon.ico（PNG-in-ICO 6 尺寸）、16-1024 PNG、Windows Square*/StoreLogo
- 替换 Tauri 脚手架默认五角星图标；GUI 重启实测 Dock 图标已生效
- 服务全量重启：server 8787（官网/文档 200）+ web 5173 + 桌面 GUI

apps/web/public/favicon.svg

@@ -1,15 +1,5 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
-  <defs>
-    <linearGradient id="g" x1="0" y1="0" x2="64" y2="64" gradientUnits="userSpaceOnUse">
-      <stop offset="0" stop-color="#2563EB"/>
-      <stop offset="1" stop-color="#06B6D4"/>
-    </linearGradient>
-  </defs>
-  <rect width="64" height="64" rx="14" fill="url(#g)"/>
-  <g stroke="#fff" stroke-width="5" stroke-linecap="round" stroke-linejoin="round" fill="none">
-    <path d="M17 25h26"/>
-    <path d="M37 19l6 6-6 6"/>
-    <path d="M47 39H21"/>
-    <path d="M27 33l-6 6 6 6"/>
-  </g>
+<svg xmlns="http://www.w3.org/2000/svg" width="512" height="512" viewBox="0 0 512 512">
+  <rect width="512" height="512" rx="112" fill="#0B182C"/>
+  <path d="M200 130c-48 0-70 28-70 70v28c0 22-14 34-34 38v20c20 4 34 16 34 38v28c0 42 22 70 70 70" fill="none" stroke="#FFFFFF" stroke-width="36" stroke-linecap="round"/>
+  <path d="M312 130c48 0 70 28 70 70v28c0 22 14 34 34 38v20c-20 4-34 16-34 38v28c0 42-22 70-70 70" fill="none" stroke="#3B82F6" stroke-width="36" stroke-linecap="round"/>
 </svg>