feat: initial commit — UniFi snap-in package

Full UniFi dashboard snap-in including:
- WiFi/client/device stats with time-series snapshots
- Client Dashboard with traffic, satisfaction, signal, download charts
- Webhook alerting with debounced offline/online detection
- AP snapshot collection, client snapshot collection
- Device classification (type and OS) from OUI/hostname heuristics
- Webhook cooldown, templates, and multi-platform delivery

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

src/Models/KnownMac.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Dashboard\Unifi\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class KnownMac extends Model
+{
+    protected $table    = 'unifi_known_macs';
+    protected $fillable = ['mac_address', 'device_name', 'device_type', 'owner', 'vlan_id', 'notes'];
+
+    public function setMacAddressAttribute($value)
+    {
+        $this->attributes['mac_address'] = strtolower($value);
+    }
+}