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/plugin/src/example-workspace.ts

@@ -0,0 +1,34 @@
+import type { Plugin } from "@opencode-ai/plugin"
+import { mkdir, rm } from "node:fs/promises"
+
+export const FolderWorkspacePlugin: Plugin = async ({ experimental_workspace }) => {
+  experimental_workspace.register("folder", {
+    name: "Folder",
+    description: "Create a blank folder",
+    configure(config) {
+      const rand = "" + Math.random()
+
+      return {
+        ...config,
+        directory: `/tmp/folder/folder-${rand}`,
+      }
+    },
+    async create(config) {
+      if (!config.directory) return
+      await mkdir(config.directory, { recursive: true })
+    },
+    async remove(config) {
+      await rm(config.directory!, { recursive: true, force: true })
+    },
+    target(config) {
+      return {
+        type: "local",
+        directory: config.directory!,
+      }
+    },
+  })
+
+  return {}
+}
+
+export default FolderWorkspacePlugin