**Issue**
Having supplier pricelists with at least one vendor inaccessible to the current user can trigger an access error when creating an RFQ approval request.

**Steps to reproduce**
- Have two companies A and B and two users u1 and u2
- user u2 only have access to company A
- With user u1:
	- Create two vendors v1 and v2 without any company assigned
	- Create vendor pricelists for a product for each vendor and assign the company A to the pricelist
- Add the company B for the vendor v2
- With user u2:
	- Open approval application
	- Try to create an approval for an RFQ for that product (the vendor v1 will be automatically selected)
	- Save it -> An access error is thrown

**Cause**
Saving the approval request computes `has_no_seller`, which calls `_select_seller`: https://github.com/odoo/enterprise/blob/03c737685ff6dfc95a8bc72491646774fc426b1f/approvals_purchase/views/approval_product_line_views.xml#L9 https://github.com/odoo/enterprise/blob/03c737685ff6dfc95a8bc72491646774fc426b1f/approvals_purchase/models/approval_product_line.py#L32 https://github.com/odoo/enterprise/blob/03c737685ff6dfc95a8bc72491646774fc426b1f/approvals_purchase/models/approval_product_line.py#L62-L70 
Which filtered the right seller
https://github.com/odoo/odoo/blob/c37e76850d3ff790b76493bd1003d80e170bd4bf/addons/product/models/product_product.py#L759 
By preparing the sellers:
https://github.com/odoo/odoo/blob/c37e76850d3ff790b76493bd1003d80e170bd4bf/addons/product/models/product_product.py#L721 https://github.com/odoo/odoo/blob/c37e76850d3ff790b76493bd1003d80e170bd4bf/addons/product/models/product_product.py#L712 
Please note that `self.seller_ids` contains both sellers (even v2) By filtering the suppliers:
https://github.com/odoo/odoo/blob/c37e76850d3ff790b76493bd1003d80e170bd4bf/addons/product/models/product_supplierinfo.py#L104-L105 
But at that point, one of the supplier in `self`, can be accessed, thus an access error is thrown while trying to access its associated `partner_id`.

opw-6203910

Forward-Port-Of: odoo/enterprise#120251

Version:
- saas-18.4

Steps to reproduce:
- Create a sign template with a readonly sign item linked to an auto field.
- Use a reference record where the auto field value is 0 or False.
- Send the document for signing and try to sign it
- Observe that the readonly field is not populated with the auto-filled value.

Issue:
- Readonly sign items using auto-filled values from a linked record could not be validated when the value was 0 or False. Instead of using these values, the sign item kept its default value.

Cause:
- A previous fix was added to avoid replacing existing values with empty auto-filled values. However, the check also considered valid falsy values such as 0 and False as empty, so they were not populated into the sign item.

Fix:
- Only treat empty strings as missing auto-filled values. This allows valid values such as 0 and False to be populated correctly. Since the sign item value is stored in a text field, False is converted to the string "False" before storing it, ensuring it is preserved and correctly available during the signing flow.

Module: l10n_it_pos

Steps to reproduce:
- In the POS settings, enable "Automatic Receipt Printing";
- Enable "ePos Printer" to make the "Skip Preview Screen" option appear;
- Disable "Skip Preview Screen";
- Disable "ePos Printer";
- Set up an Italian Fiscal Printer;
- Open a POS session and process a first order.

Issue: After the first receipt, no other messages (price display, receipt, open register) are sent to the fiscal printer. A page reload is required.

Cause:
When "Automatic Receipt Printing" is true but "Skip Preview Screen" is false, a race condition occurs. `afterOrderValidation` triggers a print job while simultaneously transitioning to the `ReceiptScreen`. When the `ReceiptScreen` mounts, it triggers a second fiscal print job before the first has resolved. This creates a deadlock in `toHtml` of  `renderService`, permanently blocking the printer queue.

Solution:
Since the italian localisation sending the receipt to the fiscal printer is mandatory, the printing route is now tied to the "Skip Preview Screen" option.
UI settings are adjusted to hide the redundant auto-print checkbox when an IT fiscal printer is configured.

Community PR: https://github.com/odoo/odoo/pull/256932

[opw-5979212](https://www.odoo.com/odoo/project/49/tasks/5979212)

Forward-Port-Of: odoo/enterprise#120747
Forward-Port-Of: odoo/enterprise#112654

### Issue
Loading a large General Ledger (e.g., during an "Unfold All" action)
and retrieving display names for thousands of journal lines 
(`account.move.line`) causes excessive memory and performance overhead.

Profiling with `memray` showed that one of the main memory hotspots 
was located in `custom_label_builder`.

**Previous behavior:** Accessing `record.display_name` in a loop without
an explicit `fetch()` call triggered lazy computation of the field via
`_compute_display_name()`. When the compute method accessed stored
dependency fields (such as `name`, `ref`, `move_id`), each cache miss
went through `_fetch_field()`, which greedily loaded **all fields sharing
the same prefetch group** on the model, far beyond the dependencies of
`display_name` alone. This caused the ORM cache to be filled with many
unnecessary stored fields for every record in the prefetch set.

---

### Dataset Volume
The performance metrics were captured using a dataset consisting of:
* **455,694** Journal Items (`account.move.line`)
* **19,947** Journal Entries (`account.move`)

---

### Solution
Add a single `fetch(['display_name'])` call on the browsed recordset.
By calling `fetch(['display_name'])` upfront, the ORM goes through 
`_determine_fields_to_fetch(['display_name'])`, which walks
only the declared `field_depends` of `display_name` and fetches **only
those specific stored fields**. nothing more.

---

### Impact & Results

| Metric | Before Optimization | After Optimization | Change / Note |
| :--- | :--- | :--- | :--- |
| **Peak Memory** | ~856 MB | ~223 MB | ~74% reduction |
| **Execution Time** | 2.48s | 2.13s | About the same time with multiple tries |

OPW-6275158