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/_time_range.html

@@ -0,0 +1,15 @@
+{#
+  Reusable time-range selector.
+  Requires `current_range` to be in template context.
+  Places a hidden input #time-range (name="range") that HTMX hx-include picks up,
+  plus a visible button group that calls setTimeRange() defined in base.html.
+#}
+<div style="display:flex;align-items:center;gap:0.2rem;">
+  <input type="hidden" id="time-range" name="range" value="{{ current_range }}">
+  {% for key in ["1h", "6h", "24h", "7d", "30d"] %}
+  <button type="button"
+          class="range-btn{% if current_range == key %} active{% endif %}"
+          data-range="{{ key }}"
+          onclick="setTimeRange('{{ key }}')">{{ key }}</button>
+  {% endfor %}
+</div>