Normalize labor category sort_order + fix increment step to 10

Migration renumbers all categories per company as 10, 20, 30… to
eliminate existing duplicates. Observer now increments by 10 instead
of 1 to leave headroom between positions.

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

database/migrations/2026_09_08_110000_normalize_labor_category_sort_order.php

@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        $companies = DB::table('companies')->pluck('id');
+
+        foreach ($companies as $companyId) {
+            $rows = DB::table('labor_categories')
+                ->where('company_id', $companyId)
+                ->orderBy('sort_order')
+                ->orderBy('id')
+                ->pluck('id');
+
+            foreach ($rows as $i => $id) {
+                DB::table('labor_categories')
+                    ->where('id', $id)
+                    ->update(['sort_order' => ($i + 1) * 10]);
+            }
+        }
+    }
+
+    public function down(): void {}
+};