feat: rename to FabledScryer, multi-dashboard system, plugin management, branding

- Rename package fablednetmon → fabledscryer throughout
- Multi-dashboard: ownership, per-user defaults, HTMX edit (add/remove/reorder)
- Read-only share tokens scoped to individual dashboards
- Dashboard edit is HTMX-driven (no page reloads)
- Plugin management system: remote catalog, download/install, hot-reload, in-app restart
- plugin_index.py: fetch/cache remote index.yaml; default URL → bvandeusen/fabledscryer-plugins
- plugin_manager.py: download_and_install_plugin, hot_reload_plugin, restart_app
  - ZIP extraction handles GitHub archive formats (name-v1.0.0/, name-main/)
- Settings split into tabbed sections: General, Notifications, Ansible, Plugins
- Plugins tab: catalog browser (HTMX), install/activate/update/restart actions
- UI/branding: dark palette (#07071a), crystal ball SVG logo, animated star field,
  Libertinus Serif applied to headings, nav, labels, and section titles
- Widget registry (core/widgets.py) for dashboard plugin integration
- UPS widget.html (dashboard card) and settings/_tabs.html include
- Migrations 0005–0008: dashboards, is_default, ownership, share tokens
- docs/plugins/: writing-a-plugin.md updated with publishing guide,
  index.yaml.example template for fabledscryer-plugins repo

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

fabledscryer/templates/settings/_install_result.html

@@ -0,0 +1,20 @@
+{# settings/_install_result.html — inline result after install/reload action #}
+<div id="catalog-result-{{ name }}"
+     style="margin-top:0.6rem;padding:0.5rem 0.75rem;border-radius:5px;font-size:0.82rem;
+            background:{% if success %}var(--green-dim){% else %}var(--red-dim){% endif %};
+            color:{% if success %}var(--green){% else %}#ff8090{% endif %};">
+  {{ message }}
+  {% if restart_required %}
+  &nbsp;·&nbsp;
+  <form method="post" action="/settings/plugins/restart/"
+        hx-post="/settings/plugins/restart/"
+        hx-target="#restart-banner"
+        hx-swap="outerHTML"
+        style="display:inline;margin:0;">
+    <button type="submit"
+            style="background:none;border:none;padding:0;color:var(--yellow);cursor:pointer;font-size:0.82rem;text-decoration:underline;">
+      Restart now
+    </button>
+  </form>
+  {% endif %}
+</div>