docs(panel): rename per-source section to 验证登录 · 按源

Clearer purpose naming: the table's function is per-source login
verification (test button + last result), not state management.

web/templates/logins.html

@@ -20,7 +20,7 @@
   {% if messages %}{% for m in messages %}<div class="flash">{{ m }}</div>{% endfor %}{% endif %}
 {% endwith %}
 
-<h2>登录态 · 按源</h2>
+<h2>验证登录 · 按源</h2>
 <div class="table-wrap">
 <table>
   <thead>