copy: flip visible wordmark → Roundtable

Updates nav brand, page <title> blocks across all templates, and the
read-only share view footer. Removes duplicate Roundtable heading from
login card now that the nav wordmark reads correctly.

roundtable/templates/alerts/list.html

@@ -1,5 +1,5 @@
 {% extends "base.html" %}
-{% block title %}Alerts — Fabled Scryer{% endblock %}
+{% block title %}Alerts — Roundtable{% endblock %}
 {% block content %}
 <h1 class="page-title">Alerts</h1>
 

roundtable/templates/alerts/maintenance.html

@@ -1,5 +1,5 @@
 {% extends "base.html" %}
-{% block title %}Maintenance Windows — Fabled Scryer{% endblock %}
+{% block title %}Maintenance Windows — Roundtable{% endblock %}
 {% block content %}
 <div style="display:flex;align-items:center;justify-content:space-between;margin-bottom:1.5rem;">
   <h1 class="page-title" style="margin-bottom:0;">Maintenance Windows</h1>

roundtable/templates/alerts/maintenance_form.html

@@ -1,5 +1,5 @@
 {% extends "base.html" %}
-{% block title %}New Maintenance Window — Fabled Scryer{% endblock %}
+{% block title %}New Maintenance Window — Roundtable{% endblock %}
 {% block content %}
 <div style="max-width:560px;margin:2rem auto;">
   <h1 class="page-title">New Maintenance Window</h1>

roundtable/templates/alerts/rules_form.html

@@ -1,5 +1,5 @@
 {% extends "base.html" %}
-{% block title %}{% if rule %}Edit Rule{% else %}New Alert Rule{% endif %} — Fabled Scryer{% endblock %}
+{% block title %}{% if rule %}Edit Rule{% else %}New Alert Rule{% endif %} — Roundtable{% endblock %}
 {% block content %}
 <div style="max-width:600px;margin:2rem auto;">
   <h1 class="page-title">{% if rule %}Edit Rule{% else %}New Alert Rule{% endif %}</h1>