Add admin dashboard, Umami beacon, README

templates/admin_login.html

@@ -0,0 +1,11 @@
+{% extends "base.html" %}
+{% block body %}
+<div class="form-card card">
+  <h2>Admin</h2>
+  <form method="post">
+    <label>Admin password</label>
+    <input type="password" name="password" required autofocus>
+    <input type="submit" value="Unlock">
+  </form>
+</div>
+{% endblock %}