This fix prevents an error from appearing when users choose the action to send invoices by post. It improves reliability for invoice processing and avoids an interruption in a common accounting workflow.

Description of the issue/feature this PR addresses:
- Traceback on "Send Invoices by post"

<strong>Issue: https://www.odoo.com/web#id=681170&view_type=form&model=project.issue&action=963&active_id=681&menu_id=4720</strong>

Current behavior before PR:
- Action menu Click on 'Send Invoices by post' give a traceback

Desired behavior after PR is merged:
- Solved traceback
## 

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

An outdated window auto-refresh setting has been removed because it has not been supported for years. This cleanup reduces confusion for administrators and developers without changing currently supported user workflows.

This feature is no longer supported for years.

The budget management module was migrated to Odoo's newer internal framework and its files were reorganized. This should make the feature easier to maintain and test without changing the core budgeting workflow for users.

Task: https://www.odoo.com/web#id=12160&view_type=form&model=project.task&action=327&menu_id=4720

The product-related code was migrated to a newer internal framework, improving maintainability and consistency across pricing, delivery, accounting, and stock workflows. Existing pricing tests were also converted to a more reliable automated test format, helping protect business-critical product pricing behavior over time.