feat: Implement price list management and import functionality

- Added ListinoRelationManager for managing price lists associated with models.
- Introduced ImportaListiniAction for importing price lists from Excel files.
- Created ListinoPrezzo model to represent price entries in the database.
- Developed ListinoExcelParser for parsing Excel files containing price lists.
- Implemented ListinoImporter to handle the import logic and associations.
- Added migration for creating listino_prezzi table and converting measures to mm.
- Updated frontend logic to handle new price list features and validations.
- Enhanced tests for price list import and conversion functionalities.

backoffice/app/Models/ListinoPrezzo.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class ListinoPrezzo extends Model
+{
+    protected $table = 'listino_prezzi';
+
+    protected $fillable = [
+        'modello_id', 'larghezza', 'altezza', 'prezzo',
+    ];
+
+    protected $casts = [
+        'larghezza' => 'integer',
+        'altezza' => 'integer',
+        'prezzo' => 'float',
+    ];
+
+    public function modello(): BelongsTo
+    {
+        return $this->belongsTo(Modello::class);
+    }
+
+    protected static function booted(): void
+    {
+        // Le modifiche manuali dal pannello aggiornano la data del listino del modello.
+        $tocca = fn (ListinoPrezzo $prezzo) => $prezzo->modello?->update(['listino_aggiornato_at' => now()]);
+
+        static::saved($tocca);
+        static::deleted($tocca);
+    }
+}