The Google Spreadsheet module has been migrated to Odoo's newer application structure and API conventions. This keeps the integration maintainable and aligned with current Odoo standards, reducing future upgrade risk without changing the core business workflow.

Task: https://www.odoo.com/web#id=12148&view_type=form&model=project.task&menu_id=3942&action=327
Pad: https://pad.odoo.com/p/r.dF6IczDDl4hnZHMg

This update modernizes older internal accounting code without changing the main accounting features users rely on. It should make the accounting module easier to maintain and support future improvements with lower technical risk.

Description of the issue/feature this PR addresses:

Current behavior before PR:

Desired behavior after PR is merged:
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