feat: add previous configuration handling for user selections in quotes

- Implemented session storage management for the last configuration choices made by the user.
- Added functionality to prompt users when changing models to retain their previous selections.
- Introduced methods to apply previous choices to the newly loaded model, including finishes, handles, glass types, and options.
- Enhanced user experience by ensuring selections are automatically applied where applicable.

backoffice/app/Models/Sistema.php

@@ -24,6 +24,27 @@ class Sistema extends Model
         return $this->hasMany(Modello::class);
     }
 
+    public function finiture(): HasMany
+    {
+        return $this->hasMany(Finitura::class);
+    }
+
+    public function vetri(): HasMany
+    {
+        return $this->hasMany(Vetro::class);
+    }
+
+    public function regoleVetro(): HasMany
+    {
+        return $this->hasMany(RegolaVetro::class);
+    }
+
+    /** Opzioni del sistema (senza quelle personalizzate per modello). */
+    public function opzioni(): HasMany
+    {
+        return $this->hasMany(Opzione::class)->whereNull('modello_id');
+    }
+
     public function scopeAttivi(Builder $query): Builder
     {
         return $query->where('attivo', true)->orderBy('ordine')->orderBy('id');