Faza 2: multi-tenancy + Filament dual panels + seed PSauto

Schema centrală:
- companies (slug unique, status, plan_id, settings JSON, trial/active dates)
- super_admins (operator platform)
- plans (free/basic/pro)

Schema tenant (toate cu company_id NOT NULL):
- users (UNIQUE company_id+email)
- clients
- vehicles

Tenancy core:
- App\Tenancy\TenantManager singleton
- App\Models\Concerns\BelongsToTenant trait + TenantScope
- ResolveTenant middleware (slug → Company, 404 pentru rezervate/missing)
- CheckTenantStatus middleware (suspended/expired/archived)
- Fail-safe: TenantScope returns 0 rows când tenant nu e rezolvat

Auth guards:
- 'central' guard cu super_admins provider (panou platform)
- 'web' guard cu users provider (per-tenant)

Filament panels:
- CentralPanelProvider la service.mir.md/admin
- TenantPanelProvider la <slug>.service.mir.md/app
- CompanyResource (central): CRUD companii cu status badge + filtre
- ClientResource (tenant): CRUD clienți cu status, sursă, sold
- VehicleResource (tenant): CRUD mașini cu marcă/model/VIN

Seed:
- 3 plans (free/basic/pro)
- super-admin: vasyka.moraru@gmail.com / admin123
- demo company 'psauto' cu admin user admin@psauto.md / admin123
- 3 clienți + 3 mașini preluate din AutoCRM.html

Bootstrap:
- TrustProxies (Cloudflare→Traefik HTTPS detection)
- forceScheme/forceRootUrl când APP_URL e HTTPS
- Helper global tenant() în app/helpers.php (autoload via composer)
- RUN_SEED env var în entrypoint pentru db:seed condiționat

app/Models/Concerns/BelongsToTenant.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Models\Concerns;
+
+use App\Models\Central\Company;
+use App\Models\Scopes\TenantScope;
+use App\Tenancy\TenantManager;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/**
+ * Trait applied on every tenant-scoped Eloquent model.
+ *  - Adds the global TenantScope so every query is filtered by company_id.
+ *  - On create, auto-fills company_id from the current tenant.
+ *  - Provides a `company()` relationship.
+ */
+trait BelongsToTenant
+{
+    protected static function bootBelongsToTenant(): void
+    {
+        static::addGlobalScope(new TenantScope);
+
+        static::creating(function ($model) {
+            if (empty($model->company_id)) {
+                $tenant = app(TenantManager::class);
+                if ($tenant->isResolved()) {
+                    $model->company_id = $tenant->currentId();
+                }
+            }
+        });
+    }
+
+    public function company(): BelongsTo
+    {
+        return $this->belongsTo(Company::class);
+    }
+}