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/tui/test/plugin/slots.test.tsx

@@ -0,0 +1,38 @@
+/** @jsxImportSource @opentui/solid */
+import { expect, test } from "bun:test"
+import { createSlot, createSolidSlotRegistry, testRender, useRenderer } from "@opentui/solid"
+import { onMount } from "solid-js"
+
+type Slots = {
+  prompt: {}
+}
+
+test("replace slot mounts plugin content once", async () => {
+  let mounts = 0
+
+  const Probe = () => {
+    onMount(() => {
+      mounts += 1
+    })
+    return <box />
+  }
+
+  const App = () => {
+    const registry = createSolidSlotRegistry<Slots>(useRenderer(), {})
+    const Slot = createSlot(registry)
+    registry.register({ id: "plugin", slots: { prompt: () => <Probe /> } })
+
+    return (
+      <Slot name="prompt" mode="replace">
+        <box />
+      </Slot>
+    )
+  }
+
+  const app = await testRender(() => <App />)
+  try {
+    expect(mounts).toBe(1)
+  } finally {
+    app.renderer.destroy()
+  }
+})