fix: central company view page 404 + broken stats query

The /admin/companies/{id} view page (ViewCompany extends Page) 404'd because
the {record} route param could arrive as a JSON-encoded model (Livewire typed-
property hydration), so findOrFail() received a non-id and threw
ModelNotFoundException. Added resolveRecordKey() to normalize scalar id / model
/ JSON-string down to the integer key.

Also fixed getStats() referencing non-existent parts columns `stock` /
`low_stock_threshold` (real columns are `qty` / `min_qty`), which would 500 the
page once mount resolved.

Added CentralCompanyViewTest as regression (asserts 200 + company name). Full
suite: 100 passed.

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

tests/Feature/CentralCompanyViewTest.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\Central\Company;
+use App\Models\Central\Plan;
+use App\Models\Central\SuperAdmin;
+use App\Tenancy\TenantManager;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class CentralCompanyViewTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_company_view_page_loads_for_existing_record(): void
+    {
+        $plan = Plan::create(['name' => 'Free', 'slug' => 'free', 'price' => 0, 'features' => []]);
+        $company = Company::create([
+            'plan_id' => $plan->id, 'slug' => 'viewco', 'name' => 'View Co',
+            'status' => 'active',
+        ]);
+
+        $admin = SuperAdmin::create([
+            'name' => 'Op', 'email' => 'op@example.com',
+            'password' => bcrypt('secret'), 'is_active' => true, 'role' => 'owner',
+        ]);
+
+        app(TenantManager::class)->setCurrent(null);
+
+        $response = $this->actingAs($admin, 'central')
+            ->get("http://service.mir.md/admin/companies/{$company->id}");
+
+        $response->assertStatus(200);
+        $response->assertSee('View Co');
+    }
+}