chore: 将前端移动到 client/ 目录，准备合并为单仓库

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

client/rsbuild.config.ts

@@ -0,0 +1,43 @@
+import { defineConfig } from "@rsbuild/core"
+import { pluginVue } from "@rsbuild/plugin-vue"
+import { NaiveUiResolver } from "unplugin-vue-components/resolvers"
+import Components from "unplugin-vue-components/rspack"
+
+export default defineConfig({
+  plugins: [pluginVue()],
+  html: {
+    template: "./index.html",
+  },
+  source: {
+    include: [/node_modules[\\/]marked[\\/]/],
+    entry: {
+      index: "./src/main.ts",
+    },
+  },
+  output: {
+    target: "web",
+    polyfill: "usage",
+  },
+  tools: {
+    rspack: {
+      plugins: [
+        Components({
+          resolvers: [NaiveUiResolver()],
+        }),
+      ],
+    },
+  },
+  server: {
+    proxy: {
+      "/media": {
+        target: process.env.PUBLIC_WEB_URL,
+        changeOrigin: true,
+      },
+      "/ws": {
+        target: process.env.PUBLIC_WEB_URL,
+        ws: true,
+        changeOrigin: true,
+      },
+    },
+  },
+})