refactor(nav): collapse single-item groups + fix ungrouped CRM resources

Previously nav had 12 groups, several with just 1 item. Now 8 clean
groups, no orphans:

- Anvelope (1 item) → merged into Service (Seturi anvelope)
- Stoc & Finanțe (1 item) → merged into Depozit (Import factură Excel)
- Tinichigerie (1 item) → merged into Service (Tinichigerie / Detailing)
- Subcontractare (2 items) → merged into Service (Lucrări terți,
  Subcontractori)
- Integrări moved from Marketing → Admin (it's a config concern, not
  a marketing feature)
- ClientResource + VehicleResource were ungrouped → added to CRM

Final groups:
  Admin(8) · Analiză(4) · CRM(5) · Depozit(10) · Finanțe(6) ·
  Magazin(2) · Marketing(3) · Service(11)

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

app/Filament/Tenant/Resources/VehicleResource.php

@@ -24,6 +24,11 @@ class VehicleResource extends Resource
         return __('nav.label.Automobile');
     }
 
+    public static function getNavigationGroup(): ?string
+    {
+        return __('nav.group.CRM');
+    }
+
     protected static ?string $modelLabel = null;
 
     public static function getModelLabel(): string