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/cliente/src/App.vue

@@ -127,7 +127,7 @@ onMounted(loadCarrello)
             <p class="item-title">{{ item.nome_modello || 'Prodotto' }}</p>
             <p class="item-sub">
               <span v-if="item.sistema">{{ item.sistema }}</span>
-              <span v-if="item.larghezza && item.altezza"> · {{ item.larghezza }}×{{ item.altezza }} cm</span>
+              <span v-if="item.larghezza && item.altezza"> · {{ item.larghezza }}×{{ item.altezza }} mm</span>
             </p>
             <div class="conf">
               <div v-for="row in item.configurazione" :key="row.label">