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/desktop/src-tauri/Cargo.toml

@@ -22,5 +22,9 @@ tauri = { version = "2", features = [] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 reqwest = { version = "0.12", default-features = false, features = ["rustls-tls", "json"] }
-tokio = { version = "1", features = ["time"] }
+tokio = { version = "1", features = ["macros", "rt-multi-thread", "sync", "time", "net"] }
 url = "2"
+tokio-tungstenite = { version = "0.24", features = ["rustls-tls-webpki-roots"] }
+futures-util = "0.3"
+uuid = { version = "1", features = ["v4"] }
+http = "1"