The base_gengo module was reorganized into a cleaner file structure and updated to Odoo's newer development framework. This should make the translation service integration easier to maintain without changing day-to-day user workflows.

Description of the issue/feature this PR addresses:

Current behavior before PR:

Desired behavior after PR is merged:
## 

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This update modernizes the Resource scheduling area and related integrations so calendars, leave intervals, payroll, holidays, project issues, and stock calendars continue to work correctly on the newer Odoo API. It also refreshes tests from older YAML cases to Python unit tests, improving reliability for future changes.

[Resource]: MIgrate to new api.

Task: https://www.odoo.com/web?#id=12717&view_type=form&model=project.task&menu_id=3942&action=327
Pad: https://pad.odoo.com/p/r.HVRfO2VpgIBXW4xh

The Gengo translation integration was reorganized and updated to work with Odoo's newer internal framework. This helps keep automated translation features maintainable and compatible without changing the core business workflow.

- Task : https://www.odoo.com/web#id=12209&view_type=form&model=project.task&menu_id=3942&action=327
- Pad : https://pad.odoo.com/p/r.4YJMn6R8itJDcfnQ

This pull request migrates several stock-related modules to Odoo's newer internal framework and cleans up related code. It improves maintainability for inventory, sales stock flows, purchasing, product pricing history, dropshipping, landed costs, and stock accounting while preserving business functionality.

<strong>Task:</strong> https://www.odoo.com/web#id=13132&view_type=form&model=project.task&menu_id=3942&action=327
<strong>Pad:</strong> https://pad.odoo.com/p/r.dTbdXwkcpfrYp0Ww

The module import feature was updated to use Odoo's newer internal framework. This keeps the tool maintainable and compatible with the latest platform standards without changing the business workflow.

Task: https://www.odoo.com/web?#id=12346&view_type=form&model=project.task&action=327
Pad: https://pad.odoo.com/p/r.qLBqdiKpoSjcFVeO

This update reorganizes and modernizes several inventory-related add-ons, including stock accounting, dropshipping, and landed costs. It should make these areas easier to maintain and evolve, with limited direct change for day-to-day users.

<strong>Task:</strong> https://www.odoo.com/web#id=13132&view_type=form&model=project.task&menu_id=3942&action=327
<strong>Pad:</strong> https://pad.odoo.com/p/r.dTbdXwkcpfrYp0Ww