feat: add fixed asset classes management page and embed functionality

- Implemented a new page for managing fixed asset classes with full CRUD functionality.
- Added filtering options for searching classes by code, description, type, and fraction.
- Integrated dialogs for inserting, editing, and deleting classes with validation.
- Enhanced error handling and user feedback with toast notifications.
- Created an embedded iframe for the fixed asset classes page in the merchandise section.

backend/api/v1/modules/a76/classes/models.py

@@ -75,7 +75,7 @@ class Class(Base, TenantScopedMixin, TimestampMixin):
     )  # UNIMED - homologated from UNIMEDIDA
 
     # Tariff fractions
-    fraction: Mapped[Optional[str]] = mapped_column(String(10))  # FRACCION
+    fraction: Mapped[Optional[str]] = mapped_column(String(20))  # FRACCION
     us_fraction: Mapped[Optional[str]] = mapped_column(
         String(16)
     )  # FRACCIONAME - US tariff fraction