This update enables users to send multiple attachments when sending invoices through the Peppol network. The attachments are now embedded within the invoice XML file using a standard ‘AdditionalDocumentReference’ tag, streamlining the process for international transactions. This improves compatibility and efficiency for Peppol-related invoicing.

[IMP] account: multiple embed files peppol

This commit allows user to send multiple attachments through peppol. The attachments will be embedded into the xml under the `AdditionalDocumentReference` tags

task-5103539

Forward-Port-Of: odoo/odoo#238936
Forward-Port-Of: odoo/odoo#234339

This update enhances Odoo's tax calculations to better handle situations where taxes are based on volume, such as sales of goods by weight or quantity. This change, requested during Odoo Exp 2025, ensures more accurate tax calculations for businesses with volume-based pricing. It impacts the account_tax_python module.

The use case to cover is when you have a volume based tax.

Requested during Odoo Exp 2025.

---
I confirm I have signed the CLA and read the PR guidelines at www.odoo.com/submit-pr

Forward-Port-Of: odoo/odoo#238140
Forward-Port-Of: odoo/odoo#232146

This update adds a new 'Update Document' button within sign templates, allowing users to easily reuse common layouts across multiple sign templates. This streamlines the process of creating sign documents by duplicating a template and swapping in a different PDF, saving time and ensuring consistency.

Adds the 'Update Document' button in the template edition for allowing changing the current document to another pdf by
duplicating the current template and replacing the document in the new template.

This is a super useful feature for re-using common layouts of sign items between different sign templates.

task-5254140