feat: maintenance windows, reports, uptime widget, alert improvements

- Add maintenance window scheduling to suppress alerts during planned
  downtime (model, routes, templates)
- Add weekly email/webhook reports with host summary (core/reports.py,
  Settings → Reports tab)
- Add host uptime history widget with per-check sparkline view
- Expand alert rules: dynamic metric catalog for plugin sources,
  per-rule HTMX field loading, maintenance window awareness
- Register additional dashboard widgets (uptime, SNMP, UniFi, UPS)
- Add Settings → Reports tab configuration

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

fabledscryer/templates/hosts/list.html

@@ -3,7 +3,10 @@
 {% 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;">Hosts</h1>
-    <a class="btn" href="/hosts/new">Add Host</a>
+    <div style="display:flex;gap:0.5rem;">
+        <a class="btn btn-ghost" href="/hosts/uptime">SLA</a>
+        <a class="btn" href="/hosts/new">Add Host</a>
+    </div>
 </div>
 {% if hosts %}
 <div class="card-flush">
@@ -16,6 +19,9 @@
                 <th style="text-align:center;">Ping</th>
                 <th style="text-align:center;">Latency</th>
                 <th style="text-align:center;">DNS</th>
+                <th style="text-align:center;" title="Uptime last 24 hours">24h</th>
+                <th style="text-align:center;" title="Uptime last 7 days">7d</th>
+                <th style="text-align:center;" title="Uptime last 30 days">30d</th>
                 <th></th>
             </tr>
         </thead>
@@ -23,6 +29,7 @@
             {% for host in hosts %}
             {% set ping = latest_pings.get(host.id) %}
             {% set dns = latest_dns.get(host.id) %}
+            {% set ut = uptime.get(host.id, {}) %}
             <tr>
                 <td>{{ host.name }}</td>
                 <td style="color:var(--text-muted);">{{ host.address }}</td>
@@ -64,6 +71,24 @@
                         <span class="dot dot-down" title="Failed"></span>
                     {% endif %}
                 </td>
+                {% for window in ["24h", "7d", "30d"] %}
+                {% set pct = ut.get(window) %}
+                <td style="text-align:center;font-size:0.82rem;font-family:ui-monospace,monospace;">
+                    {% if not host.ping_enabled %}
+                        <span style="color:var(--text-dim);">—</span>
+                    {% elif pct is none %}
+                        <span style="color:var(--text-muted);">—</span>
+                    {% elif pct >= 99.9 %}
+                        <span style="color:var(--green);">{{ "%.1f"|format(pct) }}%</span>
+                    {% elif pct >= 99 %}
+                        <span style="color:var(--yellow);">{{ "%.1f"|format(pct) }}%</span>
+                    {% elif pct >= 95 %}
+                        <span style="color:var(--orange);">{{ "%.1f"|format(pct) }}%</span>
+                    {% else %}
+                        <span style="color:var(--red);">{{ "%.1f"|format(pct) }}%</span>
+                    {% endif %}
+                </td>
+                {% endfor %}
                 <td class="td-actions">
                     <a href="/hosts/{{ host.id }}/edit" class="btn btn-sm btn-ghost" style="margin-right:0.5rem;">Edit</a>
                     <form method="post" action="/hosts/{{ host.id }}/delete" style="display:inline;">