feat: Introduce client management and integration updates

- Added client_id field to StoreTenantRequest and UpdateTenantRequest for tenant management.
- Updated TenantResource to include client_id in the response.
- Created migration to establish clients table and link tenants to clients.
- Migrated existing tenant integrations to client_integrations table.
- Grouped specific tenants under a shared client (OnTicket) in a new migration.
- Updated seeders to reflect new client structure and relationships.
- Adjusted integration configurations to require client instead of tenant.
- Added tests for client integration functionality and ensured existing tests reflect the new client structure.

app/Domains/Client/Models/Client.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Domains\Client\Models;
+
+use App\Domains\Integration\Models\ClientIntegration;
+use App\Domains\Tenant\Models\Tenant;
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+#[Fillable(['code', 'name'])]
+class Client extends Model
+{
+    public function getRouteKeyName(): string
+    {
+        return 'code';
+    }
+
+    /** @return HasMany<Tenant, $this> */
+    public function tenants(): HasMany
+    {
+        return $this->hasMany(Tenant::class);
+    }
+
+    /** @return HasMany<ClientIntegration, $this> */
+    public function integrations(): HasMany
+    {
+        return $this->hasMany(ClientIntegration::class);
+    }
+}