feat(l4d2-web): add hostname edit form to server detail page

l4d2web/templates/server_detail.html

@@ -12,6 +12,16 @@
     <div><dt>Port</dt><dd><a href="steam://run/550//+connect%20{{ connect_host }}:{{ server.port }}">{{ server.port }}</a></dd></div>
     <div><dt>Blueprint</dt><dd>{% if blueprint %}<a href="/blueprints/{{ blueprint.id }}">{{ blueprint.name }}</a>{% endif %}</dd></div>
     <div><dt>RCON Password</dt><dd><span class="password-mask" data-password-field="{{ server.id }}">••••••••••••</span><span class="password-value" data-password-field="{{ server.id }}" hidden>{{ server.rcon_password }}</span> <button class="link-button" data-password-toggle="{{ server.id }}" aria-label="Show RCON password">show</button></dd></div>
+    <div><dt>Hostname</dt>
+      <dd>
+        <form method="post" action="/servers/{{ server.id }}" class="inline-save">
+          <input type="hidden" name="csrf_token" value="{{ session.get('csrf_token', '') }}">
+          <input name="hostname" value="{{ server.hostname }}" placeholder="{{ g.user.username }} {{ server.name }}" maxlength="128">
+          <button type="submit">Save</button>
+          <span class="field-hint">Leave empty for auto: "{{ g.user.username }} {{ server.name }}"</span>
+        </form>
+      </dd>
+    </div>
   </dl>
 
   <h2 class="section-title">Actions</h2>

l4d2web/tests/test_l4d2_facade.py

@@ -431,8 +431,7 @@ def test_initialize_server_resolves_fallback_hostname(
     initialize_server(server_id)
 
     assert len(spec_contents) == 1
-    assert "hostname" in spec_contents[0]
     # The fixture creates user "alice" and server named "alpha"
-    assert '"alice alpha"' in spec_contents[0]
+    assert 'hostname "alice alpha"' in spec_contents[0]