feat(backend): complete Module 6 (dumpsites + geofence)

dumpsites table with both coordinates POINT and boundary_polygon
POLYGON (SRID 4326). Admin CRUD accepts boundary as a list of {lat,lng}
points; ring is auto-closed. Dumpsite::containsPoint() runs ST_Contains
for geofence checks (Module 10 will fire arrived_at_dumpsite from this).
dumpsite_releases schema in place — trip_id stays nullable bigint until
Module 10 adds the FK.

109 feature tests passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Http/Resources/DumpsiteResource.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Http\Resources;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+class DumpsiteResource extends JsonResource
+{
+    public function toArray(Request $request): array
+    {
+        $boundaryPoints = null;
+        if ($this->boundary_polygon) {
+            $rings = $this->boundary_polygon->getGeometries();
+            $ring = $rings->first();
+            if ($ring) {
+                $boundaryPoints = $ring->getGeometries()
+                    ->map(fn ($p) => ['lat' => $p->latitude, 'lng' => $p->longitude])
+                    ->all();
+            }
+        }
+
+        return [
+            'id' => $this->uuid,
+            'name' => $this->name,
+            'code' => $this->code,
+            'address_line' => $this->address_line,
+            'coordinates' => $this->coordinates ? [
+                'lat' => $this->coordinates->latitude,
+                'lng' => $this->coordinates->longitude,
+            ] : null,
+            'boundary_polygon' => $boundaryPoints,
+            'accepted_waste_types' => $this->accepted_waste_types,
+            'operating_hours' => $this->operating_hours,
+            'capacity_tons' => $this->capacity_tons,
+            'permit_number' => $this->permit_number,
+            'status' => $this->status,
+            'contact_person' => $this->contact_person,
+            'contact_phone' => $this->contact_phone,
+            'city_municipality' => CityMunicipalityResource::make($this->whenLoaded('cityMunicipality')),
+            'created_at' => $this->created_at?->toIso8601String(),
+        ];
+    }
+}