fix: 修正 logo 中 N 和 G 字母造型

N 添加对角线笔画（█▄ █），G 添加内横杠（█ ▀█），
避免与 O 字母造型雷同。同步更新 ui.ts 中的硬编码 wordmark。

packages/desktop/README.md

@@ -0,0 +1,19 @@
+# OpenCode Desktop
+
+The OpenCode Desktop app, built with Electron.
+
+## Development
+
+```bash
+bun install
+bun dev
+```
+
+## Build
+
+Run the `build` script to build the app's JS assets, then `package` to
+bundle the assets as an application. The resulting app will be in `dist/`.
+
+```bash
+bun run build && bun run package
+```