新增 Mantine 表单示例页面及输入校验演示

- 添加 /form 路由和表单示例菜单，通过路由懒加载拆分页面资源
- 展示文本、密码、数值、多行文本、单选、复选、开关、颜色和文件选择控件
- 使用 Cascader 展示省市区级联选择，支持搜索、清空和移动端路径列表
- 添加 MultiSelect 下拉多选与 TagsInput 自定义标签输入
- 接入 Mantine 表单状态、提交预览和重置，预览隐藏密码并仅显示文件元信息
- 添加必填标识、邮箱错误状态与提示，以及示例协议阅读和同意校验
- 将文件名换行样式封装为 CSS Module

验证：pnpm build、pnpm lint、git diff --check 均通过。

3 files changed, 316 insertions, 1 deletions

diff --git a/src/FormExample.module.css b/src/FormExample.module.css
new file mode 100644
index 0000000..913f3f9
--- /dev/null
+++ b/src/FormExample.module.css
@@ -0,0 +1,3 @@
+.fileName {
+  overflow-wrap: anywhere;
+}
diff --git a/src/FormExample.tsx b/src/FormExample.tsx
new file mode 100644
index 0000000..7f38754
--- /dev/null
+++ b/src/FormExample.tsx
@@ -0,0 +1,306 @@
+import { useState } from 'react'
+import {
+  Alert,
+  Button,
+  Checkbox,
+  Cascader,
+  Code,
+  ColorInput,
+  FileInput,
+  Group,
+  MultiSelect,
+  NumberInput,
+  Paper,
+  PasswordInput,
+  Radio,
+  Select,
+  SimpleGrid,
+  Stack,
+  Switch,
+  TagsInput,
+  Text,
+  Textarea,
+  TextInput,
+  Title,
+  useMatches,
+} from '@mantine/core'
+import { isEmail, useForm } from '@mantine/form'
+import { UploadSimpleIcon } from '@phosphor-icons/react'
+import classes from './FormExample.module.css'
+
+// 仅用于演示联动，不是完整行政区划数据。
+const regions = [
+  {
+    name: '浙江省',
+    cities: [
+      { name: '杭州市', districts: ['西湖区', '拱墅区'] },
+      { name: '宁波市', districts: ['海曙区', '鄞州区'] },
+    ],
+  },
+  {
+    name: '江苏省',
+    cities: [
+      { name: '南京市', districts: ['鼓楼区', '玄武区'] },
+      { name: '苏州市', districts: ['姑苏区', '吴中区'] },
+    ],
+  },
+]
+
+const regionOptions = regions.map((province) => ({
+  value: province.name,
+  children: province.cities.map((city) => ({
+    value: city.name,
+    children: city.districts.map((district) => ({ value: district })),
+  })),
+}))
+
+type FormValues = {
+  name: string
+  email: string
+  role: string | null
+  region: string[] | null
+  contact: string
+  interests: string[]
+  technologies: string[]
+  tags: string[]
+  color: string
+  files: File[]
+  quantity: number | string
+  password: string
+  description: string
+  notifications: boolean
+  acceptedTerms: boolean
+}
+
+const exampleErrors = { email: '邮箱格式不正确，例如 name@example.com' }
+
+export default function FormExample() {
+  const [submitted, setSubmitted] = useState<string | null>(null)
+  const withColumns = useMatches({ base: false, sm: true })
+  const form = useForm<FormValues>({
+    mode: 'controlled',
+    validateInputOnBlur: true,
+    initialErrors: exampleErrors,
+    initialValues: {
+      name: '',
+      email: 'invalid-email',
+      role: null,
+      region: null,
+      contact: 'email',
+      interests: [],
+      technologies: [],
+      tags: [],
+      color: '#228be6',
+      files: [],
+      quantity: 1,
+      password: '',
+      description: '',
+      notifications: false,
+      acceptedTerms: false,
+    },
+    validate: {
+      name: (value) => value.trim() ? null : '请输入名称',
+      email: (value) => !value.trim() ? '请输入邮箱' : isEmail(exampleErrors.email)(value.trim()),
+      role: (value) => value ? null : '请选择角色',
+      quantity: (value) => typeof value === 'number' && Number.isInteger(value) && value >= 0 && value <= 100
+        ? null : '请输入 0–100 之间的整数',
+      password: (value) => value && value.length < 8 ? '密码至少需要 8 位' : null,
+      color: (value) => /^#[\da-f]{6}$/i.test(value) ? null : '请输入有效的六位 HEX 颜色',
+      acceptedTerms: (value) => value ? null : '请先阅读并同意示例协议',
+    },
+  })
+
+  function submit(values: FormValues) {
+    setSubmitted(JSON.stringify({
+      ...values,
+      password: values.password ? '已填写（不展示密码）' : '未填写',
+      files: values.files.map((file) => ({
+        name: file.name,
+        size: file.size,
+        type: file.type || '未知类型',
+      })),
+    }, null, 2))
+  }
+
+  return (
+    <Stack gap="lg">
+      <div>
+        <Title order={1}>表单示例</Title>
+        <Text c="dimmed">体验常用表单控件。提交后在本页预览结果，数据和文件不会发送到服务器。</Text>
+      </div>
+
+      <Paper withBorder p="md">
+        <form
+          onSubmit={form.onSubmit(submit, () => setSubmitted(null))}
+          onReset={(event) => {
+            event.preventDefault()
+            form.reset()
+            form.setErrors(exampleErrors)
+            setSubmitted(null)
+          }}
+          noValidate
+        >
+          <Stack gap="lg">
+            <Text size="sm" c="dimmed">带 * 的项目为必填项；离开输入框或提交时会校验。邮箱预填了错误值，用于演示错误提示。</Text>
+            <SimpleGrid cols={{ base: 1, sm: 2 }} spacing="md">
+              <TextInput
+                label="文本输入框"
+                placeholder="请输入名称"
+                required
+                {...form.getInputProps('name')}
+              />
+              <TextInput
+                label="邮箱（错误提示示例）"
+                description="修改为有效邮箱后可正常提交"
+                placeholder="name@example.com"
+                type="email"
+                autoComplete="email"
+                required
+                {...form.getInputProps('email')}
+              />
+              <Select
+                label="选择框"
+                placeholder="请选择角色"
+                data={['开发者', '设计师', '产品经理']}
+                searchable
+                clearable
+                required
+                {...form.getInputProps('role')}
+              />
+              <NumberInput
+                label="数值输入框"
+                description="数量，范围 0–100"
+                min={0}
+                max={100}
+                allowDecimal={false}
+                {...form.getInputProps('quantity')}
+              />
+              <PasswordInput
+                label="密码输入框"
+                description="选填，填写时至少 8 位"
+                placeholder="请输入示例密码"
+                autoComplete="new-password"
+                {...form.getInputProps('password')}
+              />
+            </SimpleGrid>
+
+            <Cascader
+              label="级联选择框"
+              description="选择省、市、区，使用部分示例地区"
+              placeholder="请选择省 / 市 / 区"
+              data={regionOptions}
+              withColumns={withColumns}
+              searchable
+              clearable
+              closeOnSelect
+              clearButtonProps={{ 'aria-label': '清空地区' }}
+              nothingFoundMessage="没有匹配的地区"
+              {...form.getInputProps('region')}
+            />
+
+            <SimpleGrid cols={{ base: 1, sm: 2 }} spacing="lg">
+              <MultiSelect
+                label="下拉多选框"
+                description="选择多个技术方向"
+                placeholder="请选择技术方向"
+                data={['React', 'TypeScript', 'Vite', 'Mantine', 'Node.js']}
+                searchable
+                clearable
+                clearButtonProps={{ 'aria-label': '清空技术方向' }}
+                nothingFoundMessage="没有匹配的选项"
+                {...form.getInputProps('technologies')}
+              />
+              <TagsInput
+                label="标签输入框"
+                description="输入后按 Enter 或逗号添加标签，也可选择推荐标签"
+                placeholder="输入或选择标签"
+                data={['学习', '工作', '个人项目', '开源']}
+                clearable
+                clearButtonProps={{ 'aria-label': '清空标签' }}
+                {...form.getInputProps('tags')}
+              />
+              <Radio.Group label="单选框" description="偏好的联系方式" {...form.getInputProps('contact')}>
+                <Group mt="xs">
+                  <Radio value="email" label="邮件" />
+                  <Radio value="phone" label="电话" />
+                  <Radio value="message" label="站内消息" />
+                </Group>
+              </Radio.Group>
+              <Checkbox.Group label="多选框" description="感兴趣的方向" {...form.getInputProps('interests')}>
+                <Group mt="xs">
+                  <Checkbox value="frontend" label="前端" />
+                  <Checkbox value="backend" label="后端" />
+                  <Checkbox value="design" label="设计" />
+                </Group>
+              </Checkbox.Group>
+              <ColorInput
+                label="颜色选择框"
+                format="hex"
+                swatches={['#228be6', '#40c057', '#fab005', '#fa5252', '#7950f2']}
+                {...form.getInputProps('color')}
+              />
+              <FileInput
+                label="文件上传框"
+                description="支持选择多个文件，仅展示文件信息"
+                placeholder="点击选择文件"
+                leftSection={<UploadSimpleIcon aria-hidden="true" />}
+                multiple
+                clearable
+                {...form.getInputProps('files')}
+              />
+            </SimpleGrid>
+
+            {form.values.files.length > 0 && (
+              <Stack gap="xs" aria-live="polite">
+                {form.values.files.map((file, index) => (
+                  <Text key={`${file.name}-${index}`} size="sm" className={classes.fileName}>
+                    {file.name} · {(file.size / 1024).toFixed(1)} KB
+                  </Text>
+                ))}
+              </Stack>
+            )}
+
+            <Textarea
+              label="文本框"
+              description="多行文本，例如个人介绍或备注"
+              placeholder="请输入内容"
+              autosize
+              minRows={3}
+              maxRows={8}
+              {...form.getInputProps('description')}
+            />
+            <Switch
+              label="开关：接收消息通知"
+              {...form.getInputProps('notifications', { type: 'checkbox' })}
+            />
+            <Stack gap="xs">
+              <details>
+                <summary>查看示例协议</summary>
+                <Text size="sm" c="dimmed" py="xs">
+                  本页面仅用于演示表单交互。提交内容仅在当前页面预览，文件不会上传。
+                  勾选同意用于演示提交前的校验流程，不代表订购或开通服务。
+                </Text>
+              </details>
+              <Checkbox
+                label="我已阅读并同意示例协议"
+                required
+                {...form.getInputProps('acceptedTerms', { type: 'checkbox', withError: true })}
+              />
+            </Stack>
+            <Group>
+              <Button type="submit">提交预览</Button>
+              <Button type="reset" variant="default">重置</Button>
+            </Group>
+          </Stack>
+        </form>
+      </Paper>
+
+      {submitted !== null && (
+        <Stack gap="xs">
+          <Alert title="提交成功" color="green" role="status">以下是本次提交的示例数据。</Alert>
+          <Code block>{submitted}</Code>
+        </Stack>
+      )}
+    </Stack>
+  )
+}
diff --git a/src/routes.ts b/src/routes.ts
index 83f97b6..f0a0ef8 100644
--- a/src/routes.ts
+++ b/src/routes.ts
@@ -1,4 +1,4 @@
-import { HouseIcon, InfoIcon, UserIcon } from '@phosphor-icons/react'
+import { ClipboardTextIcon, HouseIcon, InfoIcon, UserIcon } from '@phosphor-icons/react'
 import type { Icon } from '@phosphor-icons/react'
 import type { RouteObject } from 'react-router'
 import App from './App.tsx'
@@ -18,6 +18,12 @@ export const pageRoutes = [
     handle: { title: '首页', icon: HouseIcon },
   },
   {
+    id: 'form',
+    path: '/form',
+    lazy: async () => ({ Component: (await import('./FormExample.tsx')).default }),
+    handle: { title: '表单示例', icon: ClipboardTextIcon },
+  },
+  {
     id: 'about',
     path: '/about',
     handle: { title: '关于', icon: InfoIcon },