Add auth foundation and app DB management

app/templates/login.html

@@ -0,0 +1,33 @@
+{% extends "base.html" %}
+
+{% block title %}登录 · {{ app_name }}{% endblock %}
+
+{% block content %}
+<section class="panel auth-panel">
+  <p class="eyebrow">Authentication</p>
+  <h1>登录</h1>
+  <p class="lead">
+    这个页面只负责当前 Python 重构项目的基础登录能力。配置管理等页面会在后续迭代中接入。
+  </p>
+
+  {% if error_message %}
+  <div class="alert">{{ error_message }}</div>
+  {% endif %}
+
+  <form class="auth-form" method="post" action="/login">
+    <input type="hidden" name="csrf_token" value="{{ csrf_token }}">
+
+    <label>
+      <span>Username</span>
+      <input type="text" name="username" autocomplete="username" required>
+    </label>
+
+    <label>
+      <span>Password</span>
+      <input type="password" name="password" autocomplete="current-password" required>
+    </label>
+
+    <button type="submit">登录</button>
+  </form>
+</section>
+{% endblock %}