Before this commit, assignees of an automatically created recurring task occurrence never receive an assignment notification, unlike a manually assigned task.

Steps to reproduce:
1. Enable recurring tasks, create a task, assign it to user B, and set it to repeat (e.g. daily).
2. As user A, mark the task done so the next occurrence is created.
3. User B never gets an assignment notification for the new occurrence, even though they would if user A had assigned them manually.

This happens because `_create_next_occurrence()` creates the next task via `ProjectTask.copy()`. `copy()` sets `mail_auto_subscribe_no_notify=True` in its context to avoid spamming followers when a task is duplicated (e.g. the "Duplicate" button), but recurrence reuses that same `copy()` and inherits the suppression, so assignees of auto-created occurrences are silently skipped.

This commit fixes the issue by explicitly calling `_task_message_auto_subscribe_notify()` after copying the new task, with `mail_auto_subscribe_no_notify` reset to `False`. Thanks to this, assignees get notified like any other assignment, while normal manual copies keep their existing silent behaviour.

Forward-Port-Of: odoo/odoo#282651

Steps to reproduce:
- Install `l10n_fr_pdp` and `l10n_be` module
- Activate `French e-invoicing` (you need to put your DB in test mode)
  (i.e: `account_peppol.edi.mode = 'test'` in system parameter) Refer this Documentation https://www.odoo.com/documentation/19.0/applications/finance/fiscal_localizations/france.html?highlight=e%20invoicing#localizations-france-e-invoicing-fac-elec-config
- Create a Invoice and Sent with `E-invoicing`
- Run `PEPPOL: retrieve new documents` Cron
- In Invoice Other Info >  `E-Invoicing Status` should be in `Done` state
- Now Vendor Bill is created for that invoice > Cancel that bill with reason >  Check `E-Invoicing Status` response for bill(one response will be without UUID)
- Go to schedule actions > `PEPPOL: update message status`
- Run it and get the traceback: `KeyError: 'false'`

Issue:
When sending a lifecycle response to the French PDP, `_pdp_send_response` calls the `/api/pdp/1/send_response` endpoint and expects IAP to return a `message_uuid` for each response.

However, IAP return a response without a message UUID, for example: ` {'messages': [{'message_uuid': False}]}` `_pdp_send_response` currently assumes that every returned message has a valid UUID and creates an `account.peppol.response` with:
```
    'peppol_message_uuid': False
    'peppol_state': 'processing'
```
This leaves an `account.peppol.response` in `processing` state without a UUID that can be used to track it.

During the next execution of `_cron_peppol_get_message_status`, `_peppol_get_message_status` retrieves this response through `_peppol_get_documents_for_status` and builds `uuid_to_record` using `peppol_message_uuid` as the key. The resulting mapping contains the Python value `False` as a key.

The cron then calls the PDP `1/get_document` endpoint with this invalid UUID. IAP returns it as the string `'false'`, which is passed to `_peppol_process_messages_status`. The French PDP implementation tries to retrieve the corresponding record with: `uuid_to_record[uid]`

Since the mapping contains `False` while `uid` is `'false'`, this raises: `KeyError: 'false'`

This failure prevents the status cron from completing the processing of the messages.

Solution:
Avoid creating the `account.peppol.response` when IAP does not return a `message_uuid`. A response without a UUID cannot be tracked through the PDP status flow, so creating it in `processing` state only leaves an
invalid record that will later cause the status processing to fail.

opw-6453133

---
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Forward-Port-Of: odoo/odoo#281691

Current behavior:
--
With an active automation rule (base_automation) whose action creates an activity (e.g. a "Time Off Approval" activity) on hr.leave creation, every newly created time off request has a duration of 0 days / 0 hours, regardless of the requested dates.

Expected behavior:
--
The leave duration is computed from the requested dates, unaffected by the presence of an activity-creating automation rule.

Steps to reproduce:
--
- Create an automation rule on hr.leave, trigger "On Creation & Update".
- Add an action that creates an activity (type "Time Off Approval").
- Create any time off request for an employee with a working schedule.
- The request shows a duration of "0 days" (or "0 hours").

Cause of the issue:
--
When an automation set to create and update is used to create a time-off approval activity, the code for the computation of the date_from and date_to fields are run. However, in side this code is the _display_warning_error function which contains a call to compute the number_of_days and number_of_hours fields. These fields rely on the values of date_to and date_from, causing them to retrieve values that are not yet computed, which are (0,0). 

Fix:
--
Once date_from/date_to are settled at the end of _compute_date_from_to, add the duration fields (number_of_days, number_of_hours, duration_display) back to the compute queue so they are recomputed against the correct dates.

opw-6321257
---
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## Issue
When a use rmanually increases the invoiced quantity on a timesheet invoice, subsequent timesheets logged in future periods can no longer be invoiced. The system assumes that the most recent logged hours are already covered by the previously over-invoiced amount, blocking the billing of the most recent timesheet entries.

## Steps to reproduce
1. Install *Sales Timesheet* (`sale_timesheet`)
2. Create a Product P
    - Product Type: Service
    - Invoicing Policy: Based on Timesheets
    - Create on Order: (Project &) Task
3. Create an SO:
    - Customer: Any
    - Product: P (any quantity)
    - Confirm
4. Record hours on the task created:
    - 06/01/2026 (June 1st): 1 hour
    - 07/01/2026 (July 1st): 1 hour
5. Create the invoice for the June timesheet entry (by setting a timesheets period when creating the invoice), then **change the quantity to any value strictly greater than 2** and confirm.
6. Create the invoice for July
7. **An "Invalid Operation" error appears, stating that there's nothing to invoice, even though the timesheet entry from July was never invoiced.**

## Cause
Since https://github.com/odoo/odoo/commit/3b86ac3d180993239b63fd305ee0ba1f17f7eb20, the computation of the quantity to invoice changed to include the difference between the quantity delivered and the quantity already invoiced. In the flow described by the steps to reproduce above, the quantity to invoice is larger than the quantity delivered, making the `qty_to_invoice` equal to `0.0`.

https://github.com/odoo/odoo/blob/626d31fa0191bfe7ca8e1fcf177357eeeb60f2c7/addons/sale_timesheet/models/sale_order.py#L331-L334

The reason for the fix above being the partial refunding of timesheet-related invoices, we can keep that solution when working with refunded invoices, and keep the previous behavior for other cases.

This solution solves the issue in the steps to reproduce above, but was also manually tested on the issues from https://github.com/odoo/odoo/commit/3b86ac3d180993239b63fd305ee0ba1f17f7eb20 and https://github.com/odoo/odoo/commit/64cf4afabd0c5ef040cf87fc6f3125fe0bb81bbb.

opw-6485674

Forward-Port-Of: odoo/odoo#286043
Forward-Port-Of: odoo/odoo#284470

Issue:
----------------------------------------
In the Planning Gantt view, when an employee's slots are split across several rows, all of them are greyed out except the last one, which correctly displays the employee's working hours.

Steps to reproduce:
----------------------------------------
- Have an employee with a running contract.
- Create two shifts for that employee on two different projects.
- Open Planning, switch to the Gantt view, and group by Resource, then by Project.
- Only one of the two rows for that employee shows the working hours; the other is greyed out.

Cause:
----------------------------------------
The grey background is applied by the Gantt view to any cell that has no matching working period, the same way it greys out days off.

The working periods, based on the employee's work intervals are computed in `gantt_resource_employees_working_periods()` and indexed by employee id in a plain dict (`row_per_employee_id`). When the same employee appeared in several rows, each new row overwrote the previous one in the dict, so only the last row kept a reference and got its working periods filled in.

Solution:
----------------------------------------
Group the rows per employee into a list instead of a single dict entry, and append the computed `working_periods` to every row belonging to that employee.

opw-6449130

Forward-Port-Of: odoo/enterprise#128094