feat: add http, snmp, docker plugins; new widgets and routes for traefik/unifi/ups

- Add HTTP monitor plugin: endpoint checking with status history, latency tracking, time-range views
- Add SNMP plugin: OID polling, device management, metric recording
- Add Docker plugin: container status, resource usage, widget
- Traefik: access log widget, request chart widget, expanded routes
- UniFi: clients widget, devices widget, expanded poll routes
- UPS: history widget, additional routes
- Update plugin index with new entries

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

ups/routes.py

@@ -123,3 +123,50 @@ async def widget():
         on_battery_since=_on_battery_since,
         shutdown_triggered=_shutdown_triggered,
     )
+
+
+@ups_bp.get("/widget/history")
+@require_role(UserRole.viewer)
+async def widget_history():
+    """HTMX dashboard widget: Chart.js multi-line history (battery%, load%, input voltage)."""
+    from datetime import timedelta
+    import json as _json
+    hours = max(1, min(24, int(request.args.get("hours", 6) or 6)))
+    widget_id = request.args.get("wid", "0")
+
+    since = datetime.now(timezone.utc) - timedelta(hours=hours)
+    b_secs = max(60, (hours * 3600) // 80)  # ~80 buckets
+
+    bucket_col = (
+        cast(func.strftime('%s', UpsStatus.scraped_at), Integer) / b_secs
+    ).label("bucket")
+
+    async with current_app.db_sessionmaker() as db:
+        result = await db.execute(
+            select(
+                func.avg(UpsStatus.battery_charge_pct).label("battery"),
+                func.avg(UpsStatus.load_pct).label("load"),
+                func.avg(UpsStatus.input_voltage).label("voltage"),
+                func.min(UpsStatus.scraped_at).label("scraped_at"),
+                bucket_col,
+            )
+            .where(UpsStatus.scraped_at >= since)
+            .group_by(bucket_col)
+            .order_by(bucket_col)
+        )
+        history = result.all()
+
+    labels = list(range(len(history)))
+    battery = [round(r.battery or 0, 1) for r in history]
+    load = [round(r.load or 0, 1) for r in history]
+    voltage = [round(r.voltage or 0, 1) for r in history]
+
+    return await render_template(
+        "ups/widget_history.html",
+        labels_json=_json.dumps(labels),
+        battery_json=_json.dumps(battery),
+        load_json=_json.dumps(load),
+        voltage_json=_json.dumps(voltage),
+        widget_id=widget_id,
+        hours=hours,
+    )