refactor: 主要功能实现

目前的工作已经实现的功能：
- 基本 FastAPI 路由；
- 基本 AI 聊天和创作功能；
- 用户信息管理、权限验证、JWT 令牌签发和验证、端点保护；
- HTML 验证码邮件发送和验证码验证。

webui/src/components/file/SelectFileModal.vue

@@ -0,0 +1,67 @@
+<script setup lang="ts">
+import {selectFilesCom} from "@/components/file/upload-files.js";
+import {computed, ref, watch} from "vue";
+import type {UploadFileDto} from "@/types/user.js";
+import {useMessage} from "naive-ui";
+
+const MESSAGE = useMessage()
+
+const {max, extensions, loadFiles} = defineProps<{
+  max: number
+  extensions: string[]
+  loadFiles: () => Promise<UploadFileDto[]>
+}>()
+
+const showModal = defineModel("showModal", {required: true})
+
+const files = ref<UploadFileDto[]>([])
+const tempFiles = ref<UploadFileDto[]>([])
+const selectFiles = defineModel<UploadFileDto[]>("selectFiles", {required: true})
+
+function selectFile(file: UploadFileDto) {
+  if (tempFiles.value.length < max) {
+    tempFiles.value.push(file)
+    return true
+  } else {
+    MESSAGE.warning("可选择文件数量达到上限……")
+    return false
+  }
+}
+
+function removeFile(file: UploadFileDto) {
+  const i = tempFiles.value.findIndex((item) => item.id === file.id)
+  if (i >= 0) {
+    tempFiles.value.splice(i, 1)
+  }
+  return true
+}
+
+watch(showModal, async () => {
+  tempFiles.value = []  // 每次打开模态框时都重置已选文件
+  files.value = await loadFiles()
+})
+
+const tip_1 = computed(() => max > 1 ? `请选择至少 ${max} 个文件。` : "请选择一个文件。")
+const tip_2 = computed(() => `允许的文件类型：${extensions.join('、')}。`)
+</script>
+
+<template>
+  <n-modal preset="card" style="max-width: 600px; max-height: 600px;" title="选择文件"
+           content-scrollable
+           v-model:show="showModal">
+    <n-flex vertical>
+      <n-alert type="info">
+        {{ tip_1 }}
+        {{ tip_2 }}
+      </n-alert>
+      <component :is="selectFilesCom(files, selectFile, removeFile)"/>
+      <n-button type="primary" secondary @click="selectFiles = tempFiles; showModal = false;">
+        确认选择
+      </n-button>
+    </n-flex>
+  </n-modal>
+</template>
+
+<style scoped>
+
+</style>