Currently, an error is raised when generating an invoice for multiple POS orders created for the same customer in a Mexican location.

**Steps to reproduce:**
- Install `l10n_mx_edi_pos` module.
- Switch the company to a **Mexican** company.
- Create two POS orders for the same customer (ensure Invoice is disabled on the payment screen).
- Without closing the POS session, go to the backend and navigate to Orders.
- Select both orders and click **"Create Invoice"**.

**Error:**
`ValueError - Expected singleton: pos.order(5, 4)`

**Cause:**
The method `_prepare_invoice_vals()` accesses fields on `self`, assuming a single record. However, during batch invoicing, `self` can be multiple `pos.order` records. - [1]

[1] - https://github.com/odoo/enterprise/blob/6e0396b078e7c6ffc98eef5a0d21a7df80651c19/l10n_mx_edi_pos/models/pos_order.py#L130-L135

**Fix:**
Ensure the method only accesses fields on the first record, which prevents the singleton error during multi-record processing.

sentry-6563854524

**Steps to reproduce:**
1. Install `l10n_mx` and `l10n_mx_edi`.
2. Create an invoice with:
   * Enable *CFDI to Public*.
   * Confirm, then send to SAT.
3. Create a credit note with:
   * *Usage* = `Returns, discounts or bonuses` (G02).
4. Download the generated XML for the credit note.

**Observed behavior:**
- The `<UsoCFDI>` tag in the XML shows `S01` (No fiscal effects).

**Expected behavior:**
- The `<UsoCFDI>` tag should show `G02` for credit notes under regime 616 when explicitly selected.

**Root cause:**
- For regime 616 (`Público en general`), the code always defaults to `S01`.
- The condition only allowed `G02` when refunding a global invoice (`is_refund_gi`), not for normal credit notes.

**Solution:**
- Allow `G02` usage to be preserved for credit notes (tipo_de_comprobante = 'E') even when `CFDI to public` is active, as this is now permitted by SAT regulations for fiscal regime 616.

**ref:**
http://omawww.sat.gob.mx/tramitesyservicios/Paginas/documentos/catCFDI_V_4_20250820.xls

opw-5012917

Forward-Port-Of: odoo/enterprise#93071

### Steps to reproduce:
	- Open Field Service module.
	- Create a new task. In the Customer field, select “Bloem GmbH”.
	- Open the task’s project.
	- In the Invoicing tab, create a new line for any employee and any service.
	- Return to the task and in the Timesheets tab, add a new timesheet.
	- Click the Mark as done button.
	- Click the Sales order button.

### Cause:
When creating the sale order out of the fsm task we use _get_tax_included_unit_price to get the price of the SO line but we are passing the order currency twice to this method so it doesn't convert the price as when it checks the currency and the product_currency it found they are the same so no need to convert

https://github.com/odoo/odoo/blob/6653355b8bc063ceadf08af17fbf2c4a250553e6/addons/account/models/product.py#L239-L240

### Fix:
We pass the product currency instead of the order currency in order to be able to convert the price according to the currencies

opw-5045071

Forward-Port-Of: odoo/enterprise#95134
Forward-Port-Of: odoo/enterprise#94947

**Issue**
When posting a closing entry in September on a tax return report for the month of August, the generated report (PDF/XML) incorrectly shows September instead of August.

**Steps to Reproduce**
1. Install Belgian localization.
2. Go to Accounting > Reporting > Tax Return.
3. Select August as the reporting period.
4. Post the Closing Entry.
5. The report shows September as the month instead of August.

**Root Cause**
The logic in `_init_options_date` was changed in PR #89290 mutating the `options['date']['filter']` by replacing `"tax_period"` with a resolved period type (e.g., `"month"`).
As a result, the `"month"` branch was triggered later in the code, recomputing `date_from` and `date_to` based on the current date instead of the selected tax period boundaries.

**Fix**
Keep the `options['date']['filter']` unchanged (e.g., `"custom_tax_period"`). Use `period_type` field to indicate whether the tax period represents a month, quarter, or year.

Opw-5073081

Forward-Port-Of: odoo/enterprise#94322