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/settings/_tabs.html

@@ -4,6 +4,8 @@
   {% set tabs = [
     ("general",       "General",        "/settings/general/"),
     ("notifications", "Notifications",  "/settings/notifications/"),
+    ("reports",       "Reports",        "/settings/reports/"),
+    ("auth",          "Auth",           "/settings/auth/"),
     ("ansible",       "Ansible",        "/settings/ansible/"),
     ("plugins",       "Plugins",        "/settings/plugins/"),
   ] %}

fabledscryer/templates/settings/reports.html

@@ -0,0 +1,91 @@
+{# fabledscryer/templates/settings/reports.html #}
+{% extends "base.html" %}
+{% block title %}Settings — Reports — Fabled Scryer{% endblock %}
+{% block content %}
+{% set active_tab = "reports" %}
+{% include "settings/_tabs.html" %}
+
+{% if flash %}
+<div style="padding:0.75rem 1rem;border-radius:6px;margin-bottom:1.25rem;
+            background:{% if flash.ok %}var(--green-dim){% else %}var(--red-dim){% endif %};
+            border:1px solid {% if flash.ok %}var(--green){% else %}var(--red){% endif %};
+            color:{% if flash.ok %}var(--green){% else %}var(--red){% endif %};
+            font-size:0.88rem;">
+  {{ flash.message }}
+</div>
+{% endif %}
+
+<div style="max-width:560px;">
+
+  {# ── Schedule ─────────────────────────────────────────────────────────────── #}
+  <form method="post" action="/settings/reports/">
+  <div class="card" style="margin-bottom:1.25rem;">
+    <h2 class="section-title" style="margin-bottom:1.25rem;">Weekly Digest</h2>
+
+    <div class="form-group" style="display:flex;align-items:center;gap:0.75rem;">
+      <input type="checkbox" name="reports.enabled" id="reports-enabled"
+             {% if settings['reports.enabled'] %}checked{% endif %}>
+      <label for="reports-enabled" style="margin:0;">Enable weekly email digest</label>
+    </div>
+
+    <div style="display:grid;grid-template-columns:1fr 1fr;gap:1rem;margin-top:0.5rem;">
+      <div class="form-group">
+        <label>Send on day</label>
+        <select name="reports.schedule_day">
+          {% for i, day in [(0,"Monday"),(1,"Tuesday"),(2,"Wednesday"),(3,"Thursday"),(4,"Friday"),(5,"Saturday"),(6,"Sunday")] %}
+          <option value="{{ i }}" {% if settings['reports.schedule_day'] == i %}selected{% endif %}>
+            {{ day }}
+          </option>
+          {% endfor %}
+        </select>
+      </div>
+      <div class="form-group">
+        <label>At hour (UTC)</label>
+        <select name="reports.schedule_hour">
+          {% for h in range(24) %}
+          <option value="{{ h }}" {% if settings['reports.schedule_hour'] == h %}selected{% endif %}>
+            {{ "%02d:00"|format(h) }}
+          </option>
+          {% endfor %}
+        </select>
+      </div>
+    </div>
+
+    <p style="font-size:0.78rem;color:var(--text-muted);margin-top:0.25rem;">
+      Requires SMTP configured in <a href="/settings/notifications/">Notifications</a>.
+      {% if settings['reports.last_sent_at'] %}
+      Last sent: {{ settings['reports.last_sent_at'][:16] }} UTC.
+      {% endif %}
+    </p>
+
+    <div style="margin-top:1rem;">
+      <button type="submit" class="btn">Save</button>
+    </div>
+  </div>
+  </form>
+
+  {# ── Report contents ─────────────────────────────────────────────────────── #}
+  <div class="card" style="margin-bottom:1.25rem;">
+    <h2 class="section-title" style="margin-bottom:0.75rem;">Report contents</h2>
+    <div style="display:grid;gap:0.35rem;font-size:0.85rem;color:var(--text-muted);">
+      <div>• <strong style="color:var(--text);">Uptime summary</strong> — 7-day % per ping-enabled host</div>
+      <div>• <strong style="color:var(--text);">Hosts currently down</strong> — highlighted at top if any</div>
+      <div>• <strong style="color:var(--text);">Active alerts</strong> — firing, acknowledged, pending rules</div>
+      <div>• <strong style="color:var(--text);">Alert events (7d)</strong> — fired and resolved counts</div>
+      <div>• <strong style="color:var(--text);">Top Traefik routers</strong> — avg req/s over last 24h (if plugin enabled)</div>
+    </div>
+  </div>
+
+  {# ── Send now ─────────────────────────────────────────────────────────────── #}
+  <div class="card">
+    <h2 class="section-title" style="margin-bottom:0.75rem;">Send Now</h2>
+    <p style="font-size:0.85rem;color:var(--text-muted);margin-bottom:1rem;">
+      Send a report immediately regardless of schedule. Useful for testing.
+    </p>
+    <form method="post" action="/settings/reports/send-now/">
+      <button type="submit" class="btn btn-ghost">Send report now</button>
+    </form>
+  </div>
+
+</div>
+{% endblock %}