feat: add GitHub OAuth login

open-isle-cli/src/views/GithubCallbackPageView.vue

@@ -0,0 +1,32 @@
+<template>
+  <div class="loading">GitHub 登录中...</div>
+</template>
+
+<script>
+import { githubExchange } from '../utils/github'
+
+export default {
+  name: 'GithubCallbackPageView',
+  async mounted() {
+    const url = new URL(window.location.href)
+    const code = url.searchParams.get('code')
+    const state = url.searchParams.get('state')
+    const result = await githubExchange(code, state, '')
+    if (result === 'NEED_REASON') {
+      this.$router.push('/signup-reason?github=1')
+    } else {
+      this.$router.push('/')
+    }
+  }
+}
+</script>
+
+<style scoped>
+.loading {
+  height: calc(100vh - var(--header-height));
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 20px;
+}
+</style>