feat(backend): complete Module 5 (drop-off points + auto-assign)

drop_off_points (with SPATIAL INDEX on coordinates) +
drop_off_capacity_logs. Public nearby query via ST_Distance_Sphere
returns DOPs sorted by distance with distance_meters in payload.
Admin CRUD plus capacity-log endpoint. Household creation auto-assigns
to the nearest active DOP within 25km; resident can re-run the lookup
via POST /households/{uuid}/reassign-drop-off.

97 feature tests passing.

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

app/Models/DropOffCapacityLog.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class DropOffCapacityLog extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'drop_off_point_id',
+        'recorded_at',
+        'fill_percent',
+        'recorded_by_user_id',
+        'notes',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'recorded_at' => 'datetime',
+            'fill_percent' => 'integer',
+        ];
+    }
+
+    public function dropOffPoint(): BelongsTo
+    {
+        return $this->belongsTo(DropOffPoint::class);
+    }
+
+    public function recordedBy(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'recorded_by_user_id');
+    }
+}