Remove unused templates for newsletter creation, settings, and submissions; update unsubscribe confirmation link; add tests for email templates API.

templates/admin/admin_email_templates.html

@@ -0,0 +1,21 @@
+{% extends "_base.html" %} {% block title %}Email Templates{% endblock %} {%
+block heading %}Email Templates{% endblock %} {% block extra_styles %}
+<link rel="stylesheet" href="/static/css/admin.css" /> {% endblock %} {% block
+content %}
+<div class="settings-management">
+  <h2>Newsletter Confirmation Template</h2>
+  <p>Edit the HTML template used for the newsletter confirmation email.</p>
+  <div id="message"></div>
+  <form id="templateForm">
+    <div class="form-group">
+      <label for="newsletterTemplate">Template HTML</label>
+      <textarea id="newsletterTemplate" rows="15" cols="80"></textarea>
+    </div>
+    <div class="form-group">
+      <button class="btn btn-primary" type="submit">Save Template</button>
+    </div>
+  </form>
+</div>
+{% endblock %} {% block extra_scripts %}
+<script src="/static/js/admin.js"></script>
+{% endblock %}