fix: slug unique check skips soft-deleted + drop DB unique on companies.slug

DB-level unique blocks INSERT even when previous record is soft-deleted.
MariaDB doesn't support partial unique indexes, so we drop the constraint
and rely on Filament validation + provisioner check (whereNull deleted_at).

database/migrations/2026_05_07_000001_drop_companies_slug_unique.php

@@ -0,0 +1,30 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * MariaDB nu suportă partial unique indexes (UNIQUE WHERE deleted_at IS NULL).
+     * Drop unique-ul fizic și păstrăm doar index pentru performanță;
+     * unicitatea slug-ului e impusă la nivel de validare Filament + provisioner.
+     */
+    public function up(): void
+    {
+        Schema::table('companies', function (Blueprint $t) {
+            // Drop existing unique (default name companies_slug_unique).
+            try { $t->dropUnique('companies_slug_unique'); } catch (\Throwable $e) {}
+            $t->index('slug', 'companies_slug_index');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('companies', function (Blueprint $t) {
+            try { $t->dropIndex('companies_slug_index'); } catch (\Throwable $e) {}
+            $t->unique('slug', 'companies_slug_unique');
+        });
+    }
+};