refactor: rename package directory fabledscryer → roundtable

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

roundtable/templates/errors/500.html

@@ -0,0 +1,10 @@
+{% extends "base.html" %}
+{% block title %}Error — Fabled Scryer{% endblock %}
+{% block content %}
+<div style="text-align:center; padding: 4rem 2rem; font-family: var(--font-serif);">
+  <h1 style="color: var(--red); font-size: 2.5rem; margin-bottom: 0.5rem;">500</h1>
+  <p style="color: var(--text); font-size: 1.2rem; margin-bottom: 0.25rem;">The watch has faltered.</p>
+  <p style="color: var(--text-dim); margin-bottom: 1.5rem;">An unexpected error occurred. The cause has been logged.</p>
+  <a href="/" class="btn">Return to the hall</a>
+</div>
+{% endblock %}