refactor: presentation becomes http-axum adapter, absorbs templates

crates/adapters/http-axum/templates/login.html

@@ -0,0 +1,19 @@
+{% extends "base.html" %}
+{% block content %}
+<h1>Login</h1>
+{% if let Some(err) = error %}
+<p class="error">{{ err }}</p>
+{% endif %}
+<form method="POST" action="/login">
+  <label>
+    Email<br>
+    <input type="email" name="email" required autocomplete="email">
+  </label>
+  <label>
+    Password<br>
+    <input type="password" name="password" required autocomplete="current-password">
+  </label>
+  <input type="hidden" name="_csrf" value="{{ ctx.csrf_token }}">
+  <button type="submit">Login</button>
+</form>
+{% endblock %}