build: 打通 FastAPI 与 Vue 最小工程、依赖与数据库连接

后端入口、配置、Redis 与 Alembic 迁移就位；前端 Vite 工程可安装可构建。

frontend/vite.widget.config.ts

@@ -0,0 +1,44 @@
+import { defineConfig } from 'vite'
+import vue from '@vitejs/plugin-vue'
+import { resolve } from 'path'
+
+export default defineConfig({
+  plugins: [
+    vue({
+      template: {
+        compilerOptions: {
+          // Treat all tags starting with 's-' as custom elements (Polaris web components)
+          isCustomElement: (tag) => tag.startsWith('s-')
+        }
+      }
+    })
+  ],
+  build: {
+    lib: {
+      entry: resolve(__dirname, 'src/webclient/widget.ts'),
+      name: 'ChatterMateWidget',
+      fileName: 'widget',
+      formats: ['es'],
+    },
+    outDir: '../backend/assets',
+    emptyOutDir: false,
+    rollupOptions: {
+      output: {
+        format: 'es',
+        entryFileNames: 'widget.js',
+        assetFileNames: (assetInfo) => {
+          if (assetInfo.name === 'style.css') {
+            return 'widget.css'
+          }
+          // Place other assets in a subdirectory that we can ignore or clean up later
+          return 'unused/[name]-[hash][extname]'
+        },
+        chunkFileNames: 'unused/[name]-[hash].js',
+        manualChunks: undefined, // Disable code splitting
+      },
+    },
+  },
+  define: {
+    'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'production'),
+  },
+})