**Issue**
Adding a serial-tracked by-product manually on a Manufacturing Order whose BOM does not define it, can lead to inconsistencies when assigning serial numbers in the shopfloor application.

**Steps to reproduce**
- Activate by-product in the settings
- Create a product with an empty BOM (final product)
- Create another product tracked by serial number (by-product)
- Create and confirm a MO for the final product with 1 unit of the by-product
- Go to Miscellaneaous -> operation Type -> shopfloor
- Activate the option "Pre fill lot/serial numbers in shop floor"
- Return to the MO and open the shopfloor view
- Click on the '+' button next to the by-product and assign a serial number
- Try to close the production
-> A user error is raised stating that the by-product requires a serial number.

**Cause**
When the by-product is added manually on the MO, a stock move is created with an initial move line that does not contain any serial number.

Later, when assigning a serial number from the shopfloor view: https://github.com/odoo/enterprise/blob/8030b105d3fce1eef9b8965a2bfc37195f71723c/mrp_workorder/models/stock_move.py#L121-L122 a new move line containing the serial number is created: https://github.com/odoo/enterprise/blob/8030b105d3fce1eef9b8965a2bfc37195f71723c/mrp_workorder/models/stock_move.py#L116-L119 However, the original empty move line is not removed (the issue): https://github.com/odoo/enterprise/blob/8030b105d3fce1eef9b8965a2bfc37195f71723c/mrp_workorder/models/stock_move.py#L124-L125 Because `self.picking_type_prefill_shop_floor_lots` is True, but `self.byproduct_id` is an empty recordset since: https://github.com/odoo/odoo/blob/8d14665af5acf1bd391d05a5048dc701986e8b15/addons/mrp/models/mrp_production.py#L1304-L1311 https://github.com/odoo/odoo/blob/8d14665af5acf1bd391d05a5048dc701986e8b15/addons/mrp/models/mrp_production.py#L1279 Indeed, `byproduct_id` is only populated from BOM-defined by-products. As a result, while confirming the production, there is 2 sml and among them, the original one without SN, which triggers the error:
https://github.com/odoo/odoo/blob/8d14665af5acf1bd391d05a5048dc701986e8b15/addons/stock/models/stock_move_line.py#L590 https://github.com/odoo/odoo/blob/8d14665af5acf1bd391d05a5048dc701986e8b15/addons/stock/models/stock_move_line.py#L634-L635 https://github.com/odoo/odoo/blob/8d14665af5acf1bd391d05a5048dc701986e8b15/addons/stock/models/stock_move_line.py#L658-L659 https://github.com/odoo/odoo/blob/8d14665af5acf1bd391d05a5048dc701986e8b15/addons/stock/models/stock_move_line.py#L661-L669

opw-6223158

Forward-Port-Of: odoo/enterprise#118792

**Steps to reproduce:**
* Install `l10n_fr_pdp` module.
* Activate French eInvoicing in demo mode and enable "Participate in the pilot phase".
* Create an invoice for a French client and send it via the French E-Invoicing.

**Observed behavior:**
* A traceback is raised with `KeyError: 'messages'` in `_send_peppol_documents`.

**Cause:**
* `DEMO_ENDPOINTS['send_document']` in `l10n_fr_pdp` was returning `{'ppf_messages': [...]}`, missing the `messages` key that `_send_peppol_documents` in `account_peppol` unconditionally reads for flow 2.
* Additionally, the demo mock was returning `uid` instead of `uuid` inside `ppf_messages`, which does not match the real IAP response structure.
* Finally, in `l10n_fr_pdp/models/pdp_flow.py`, after successfully sending a flow 10 batch, the system attempted to log `response['uid']` despite the `_send_to_proxy()` method returning `uuid`. This caused a crash during the chatter logging step.

**Fix:**
* Fix `DEMO_ENDPOINTS['send_document']` to return `{'messages': [...]}` with `message_uuid` entries, matching the real IAP response structure for flow 2.
* Update `ppf_messages` in the demo mock to return `uuid` instead of `uid`.
* Fix `pdp_flow.py` to correctly access `response['uuid']` instead of `response['uid']` when posting the success message.

IAP Response: https://github.com/odoo/iap-apps/blob/b0462b9dded36a4d6dd45d00ddd13cd36e31807e/iap_services/l10n_fr_pdp_proxy/controllers/message_controller.py#L63

opw-6289723

Forward-Port-Of: odoo/odoo#269515