Issue:
After manually modifying the taxes on a vendor bill that generates COGS lines, confirming the vendor bill causes the taxes to revert to their original values before the manual edit. This happens because the product’s purchase taxes are applied to the generated COGS lines, which triggers the tax recomputation logic and overwrites the manually adjusted tax amounts. However, COGS lines represent internal operations and should not have taxes applied to them

Steps to reproduce:
1. Turn on Anglo-Saxon accounting
2. Turn on automatic accounting
3. Make a FIFO product category and make the valuation automatic
4. Make a new product and set the FIFO product category on it
5. Make sure the product has a vendor tax set
6. Make a purchase order for 10 of the FIFO product category at $10
7. Create and validate the receipt for 10
8. Make a sales order for 6 of the FIFO product category at $10
9. Create and validate the delivery for 6
10. Create the vendor bill for 10 the purchase order created above (make sure that there is a tax set on the vendor bill; the vendor tax that was set on the product). Make this vendor bill set for 10 at $20
11. Edit the tax at the bottom of the total
12. Confirm the vendor bill
13. Notice that the tax at the bottom of the total changes
14. Reset the vendor bill
15. Remove the purchase tax from the product
16. Confirm the vendor bill again and notice that the tax at the bottom of the total does not change this time

Cause:
On confirmation, the COGS lines on the vendor bill will be generated and “_compute_tax_ids” will be triggered on those lines. Since COGS lines have a “product_id” set on them, those lines will receive the purchase tax set on the product. Setting the “tax_ids” on those COGS lines will cause tax computation to trigger again, which will reset the manually edited tax amount to the new computed amount. However, since COGS lines come in pairs that are equal and opposite in amount, the taxes from both COGS lines will cancel out, and the new computed tax amount does not change

Solution:
Skip setting the purchase taxes of the product onto COGS lines in “_compute_tax_ids”

opw-6110692

Forward-Port-Of: odoo/odoo#267957
Forward-Port-Of: odoo/odoo#265352

### Issue
Since the introduction of the Tax Returns feature in 18.3, it was no longer possible to generate a Closing Entry as the button has been replaced by Returns
The Return mechanism implies that you need a Return Type in order to make a Closing Entry using the Validate button

Additionally, using the Generic Tax Report by default creates a risk in Multi-VAT environments, as it mixes taxes from all countries instead of isolating Peruvian taxes

### Cause
The new 18.3 accounting workflow requires at least one active Return Type associated with a country-specific report variant to display the Return options and process the closing entry Peru was relying on the Generic Tax Report, without a dedicated report variant
No Return Type was configured, which blocked Odoo's automatic VAT closing workflow and prevented the system from prompting the user to configure the required closing accounts

### Steps to reproduce
- Install `l10n_pe_reports` and `accountant`
- Switch to a PE Company
- Go to the Tax Report Before the fix, no Returns button is available for any of the existing reports, making it impossible to use Odoo's automatic process to configure the tax accounts and trigger the closing entry

### Notes
This is fixed by creating a dedicated Peruvian tax report variant directly in Enterprise that inherits from the generic tax report A custom handler is added to force the domain filtering on Peruvian taxes only, and a corresponding Return Type is defined to restore the full closing entry process safely

enterprise-pr: https://github.com/odoo/enterprise/pull/117891
opw-5978673

**Problem:**
If a vendor bill associated with a project through its analytic distribution has lines with negative subtotals, those lines are not considered in the project profitability report. An example use case is a downpayment invoice, followed by a final invoice with the downpayment amount deducted.

**Steps to Reproduce:**
- Ensure project_purchase is not installed
- Create a new project with "Billable" enabled
- Go to the project settings and create an analytic account
- Create and post a vendor bill with a line labeled "downpayment", the analytic account set, and a unit price of 5
- Duplicate the vendor bill, set the "downpayment" line unit price to -5, add a line labeled "product" with the analytic account set and a unit price of 10, and post the bill

-> Go to the project updates and see that the vendor bill costs is wrong (15)

**Solution:**
A similar bug affecting customer invoices was resolved in PR #130992. AMLs with non-zero subtotals should be considered, so the domain is adjusted accordingly.

opw-6172523

Forward-Port-Of: odoo/odoo#265378