feat: rebuild auth identity foundation flow

frontend/src/components/auth/WechatOAuthSection.vue

@@ -0,0 +1,53 @@
+<template>
+  <div class="space-y-4">
+    <button type="button" :disabled="disabled" class="btn btn-secondary w-full" @click="startLogin">
+      <span
+        class="mr-2 inline-flex h-5 w-5 items-center justify-center rounded-full bg-green-100 text-xs font-semibold text-green-700 dark:bg-green-900/30 dark:text-green-300"
+      >
+        W
+      </span>
+      {{ t('auth.oidc.signIn', { providerName }) }}
+    </button>
+
+    <div v-if="showDivider" class="flex items-center gap-3">
+      <div class="h-px flex-1 bg-gray-200 dark:bg-dark-700"></div>
+      <span class="text-xs text-gray-500 dark:text-dark-400">
+        {{ t('auth.oauthOrContinue') }}
+      </span>
+      <div class="h-px flex-1 bg-gray-200 dark:bg-dark-700"></div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { useRoute } from 'vue-router'
+import { useI18n } from 'vue-i18n'
+
+withDefaults(defineProps<{
+  disabled?: boolean
+  showDivider?: boolean
+}>(), {
+  showDivider: true,
+})
+
+const route = useRoute()
+const { t } = useI18n()
+
+const providerName = 'WeChat'
+
+function resolveWeChatOAuthMode(): 'open' | 'mp' {
+  if (typeof navigator === 'undefined') {
+    return 'open'
+  }
+  return /MicroMessenger/i.test(navigator.userAgent) ? 'mp' : 'open'
+}
+
+function startLogin(): void {
+  const redirectTo = (route.query.redirect as string) || '/dashboard'
+  const apiBase = (import.meta.env.VITE_API_BASE_URL as string | undefined) || '/api/v1'
+  const normalized = apiBase.replace(/\/$/, '')
+  const mode = resolveWeChatOAuthMode()
+  const startURL = `${normalized}/auth/oauth/wechat/start?mode=${mode}&redirect=${encodeURIComponent(redirectTo)}`
+  window.location.href = startURL
+}
+</script>

frontend/src/components/auth/__tests__/WechatOAuthSection.spec.ts

@@ -0,0 +1,74 @@
+import { mount } from '@vue/test-utils'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import WechatOAuthSection from '@/components/auth/WechatOAuthSection.vue'
+
+const routeState = vi.hoisted(() => ({
+  query: {} as Record<string, unknown>,
+}))
+
+const locationState = vi.hoisted(() => ({
+  current: { href: 'http://localhost/login' } as { href: string },
+}))
+
+vi.mock('vue-router', () => ({
+  useRoute: () => routeState,
+}))
+
+vi.mock('vue-i18n', () => ({
+  useI18n: () => ({
+    t: (key: string, params?: Record<string, string>) => {
+      if (key === 'auth.oidc.signIn') {
+        return `Continue with ${params?.providerName ?? ''}`.trim()
+      }
+      if (key === 'auth.oauthOrContinue') {
+        return 'or continue'
+      }
+      return key
+    },
+  }),
+}))
+
+describe('WechatOAuthSection', () => {
+  beforeEach(() => {
+    routeState.query = { redirect: '/billing?plan=pro' }
+    locationState.current = { href: 'http://localhost/login' }
+    Object.defineProperty(window, 'location', {
+      configurable: true,
+      value: locationState.current,
+    })
+    Object.defineProperty(window.navigator, 'userAgent', {
+      configurable: true,
+      value: 'Mozilla/5.0',
+    })
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('starts the open WeChat OAuth flow with the current redirect target', async () => {
+    const wrapper = mount(WechatOAuthSection)
+
+    expect(wrapper.text()).toContain('WeChat')
+
+    await wrapper.get('button').trigger('click')
+
+    expect(locationState.current.href).toContain(
+      '/api/v1/auth/oauth/wechat/start?mode=open&redirect=%2Fbilling%3Fplan%3Dpro'
+    )
+  })
+
+  it('uses mp mode inside the WeChat browser', async () => {
+    Object.defineProperty(window.navigator, 'userAgent', {
+      configurable: true,
+      value: 'Mozilla/5.0 MicroMessenger',
+    })
+    const wrapper = mount(WechatOAuthSection)
+
+    await wrapper.get('button').trigger('click')
+
+    expect(locationState.current.href).toContain(
+      '/api/v1/auth/oauth/wechat/start?mode=mp&redirect=%2Fbilling%3Fplan%3Dpro'
+    )
+  })
+})