feat: add RegisterForm component with field-level error handling

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/components/register/RegisterForm.vue

@@ -0,0 +1,104 @@
+<script setup lang="ts">
+import { clientRegisterSchema, type RegisterInput } from 'shared/auth-schema'
+
+const props = defineProps<{
+  captchaSvg: string
+  captchaToken: string
+}>()
+
+const emit = defineEmits<{
+  'refresh-captcha': []
+  success: []
+  error: [message: string]
+}>()
+
+const loading = ref(false)
+const formRef = ref()
+
+const state = reactive<RegisterInput>({
+  username: '',
+  password: '',
+  confirmPassword: '',
+  captchaText: '',
+})
+
+const password = computed(() => state.password)
+
+async function onSubmit() {
+  if (loading.value) return
+  loading.value = true
+  try {
+    const res = await $fetch<{ code: number; message: string; data: { id?: number; username?: string; field?: string } | null }>(
+      '/api/auth/register',
+      {
+        method: 'POST',
+        body: {
+          username: state.username,
+          password: state.password,
+          confirmPassword: state.confirmPassword,
+          captchaToken: props.captchaToken,
+          captchaText: state.captchaText,
+        },
+      }
+    )
+
+    if (res.code !== 0) {
+      const field = res.data && 'field' in (res.data || {}) ? (res.data as { field: string }).field : undefined
+      if (field && formRef.value) {
+        formRef.value.setFieldError(field, res.message)
+      } else {
+        emit('error', res.message)
+      }
+      // Auto-refresh captcha on captcha-related errors
+      if (res.message.includes('验证码')) {
+        emit('refresh-captcha')
+        state.captchaText = ''
+      }
+      return
+    }
+
+    emit('success')
+  } catch {
+    emit('error', '注册失败，请稍后重试')
+  } finally {
+    loading.value = false
+  }
+}
+</script>
+
+<template>
+  <UForm ref="formRef" :state="state" :schema="clientRegisterSchema" @submit="onSubmit">
+    <UFormField name="username" label="用户名" required class="mb-4">
+      <UInput v-model="state.username" placeholder="请输入用户名" :disabled="loading" />
+    </UFormField>
+
+    <PasswordInput
+      v-model="state.password"
+      label="密码"
+      placeholder="至少8个字符"
+      :disabled="loading"
+      class="mb-4"
+    />
+    <PasswordStrength :password="password" />
+
+    <PasswordInput
+      v-model="state.confirmPassword"
+      label="确认密码"
+      placeholder="请再次输入密码"
+      :disabled="loading"
+      class="mb-4 mt-2"
+    />
+
+    <CaptchaField
+      v-model="state.captchaText"
+      :svg="captchaSvg"
+      :loading="loading"
+      class="mb-4"
+      @refresh="emit('refresh-captcha')"
+    />
+
+    <UButton type="submit" block :loading="loading" class="mt-6">
+      {{ loading ? '注册中...' : '注册' }}
+    </UButton>
+  </UForm>
+</template>