#### Issue:
This commit adds a missing account.return.type data in the Oman localization. This is related to the new Accounting Returns #81569

The l10n_om module did not include an account.return.type record, which prevents the "Returns" button (linked to the action_open_returns) from appearing in the Tax Report. As a result, users in Oman are unable to access the Tax Closing form.

Also the l10n_om is a community module, because of that, we need to add a new enterprise module to add the related data for the tax returns.

The visibility of the button is controlled by the following condition: [Code](https://github.com/odoo/enterprise/blob/f924f120cbd04002e21c78b081e1c8006b56a4b6/account_reports/models/account_report.py#L1776)

#### Affected Versions:
18.3 and later

#### Steps to reproduce:

1.Install the l10n_om module
2.Switch to the Oman company
3.Go to Accounting > Reporting > Tax Report
4.The "Returns" button is not visible

#### Expected behavior
The "Returns" button should be visible, allowing the user to generate the closing tax form.

#### Current behavior
The button is hidden due to missing account.return.type data in the Oman localization.

OPW-4943024

**Current Behavior:**

Manual discounts are not retained when adding optional products to the order.

**Steps to Reproduce:**

1) Install the sale_subscription module.
2) Create a subscription with a recurring plan.
3) Add a product to the Optional Products section. 
4) Manually set a discount on the optional product. 
5) Click on the Add to Order Lines (cart) button.
6) A new SOL is created.

**Issue:**

The newly created SOL does not retain the manually set discount.

**Cause:**

- When the user clicks the Add to Order Lines button, the `add_option_to_order` method is triggered.
This method creates a new sale order line (SOL) using values from `_get_values_to_add_to_order`.

- In the current implementation, this method is overridden for subscription orders to exclude the 
discount value from the returned data.

https://github.com/odoo/enterprise/blob/42d829ea6e6a98f251cfffc8fb67b5320a5ada12/sale_subscription/models/sale_order_option.py#L17-L21

- This forces a recomputation of the discount based on pricelist rules, 
which unintentionally removes any manually set discount.

**Solution:**

- Only remove the discount value from the returned data and trigger recomputation 
if there is no manual discount.

- This ensures that any user-defined discount is preserved when creating the order line.

opw-4840735

Forward-Port-Of: odoo/enterprise#90423
Forward-Port-Of: odoo/enterprise#89381

After [this PR](https://github.com/odoo/enterprise/pull/81894) was merged, we are encountering below errors.

**Issue 1:**

An error occurs when attempting to connect a new bank account.

**Step to produce:**

- Install the `account_online_synchronization` module and open `invoicing`.
- Go to: `Configuration > Banks > Add a Bank Account`.
- `Add new bank > Enter Details > Connect`.

**Error:**
`TypeError: AccountOnlineLink.create_new_bank_account_action() takes 2 positional arguments but 3 were given`

**Root cause:**
It appears that removal of `@api.model` was missed in [this PR](https://github.com/odoo/enterprise/pull/89932) during the forward-port process, leading to this error.

**Fix:**
This commit removes `@api.model` so that the method behaves like a recordset method, as done in [this PR](https://github.com/odoo/enterprise/pull/81894).

**Issue 2:**

An error occurs when attempting to Setup Bank.

At [1], when an exception occurs, the method returns an empty list, and this displays the `Setup Bank` button. Upon clicking the button, an error occurs.

[1]
https://github.com/odoo/enterprise/blob/443d7d303ecb3bfcba6ac865cf0185b5070b6b9d/account_online_synchronization/models/account_journal.py#L88-L97

**Error:**
`ValueError: Expected singleton: account.online.link()`

**Root Cause:**
At [2], the JS method `fallbackConnectBank` was passing only one positional argument instead of two. However, the corresponding Python method at [3] requires two positional arguments.

[2]
https://github.com/odoo/enterprise/blob/443d7d303ecb3bfcba6ac865cf0185b5070b6b9d/account_online_synchronization/static/src/components/bank_configure/bank_configure.js#L67-L71

[3]
https://github.com/odoo/enterprise/blob/443d7d303ecb3bfcba6ac865cf0185b5070b6b9d/account_online_synchronization/models/account_online.py#L418

This commit updates the JS method `fallbackConnectBank` to pass two positional arguments as required by the python method at [3].

sentry–6745764054,6388425767

Forward-Port-Of: odoo/enterprise#90225

## [PERF] hr_referral: Send refusal notification to referrer's users

Description
-----------
Following https://github.com/odoo/enterprise/commit/764f9b6f513c90eb79935d9e8469989ea704b61b, `_send_notification` will not attach the message on the `hr.applicant` itself, so a `model` was provided.
But due to a missing `res_id`, `message_notify` will set both `model` & `res_id` to `False` since both are not specified. This leads to the creation of a `mail.message` with no `res_id` and no `model` (as `self` is an empty `mail.thread` recordset).

This leads to a performance regression when mail references need to be computed to attach to the notification in `_notify_by_email_get_base_mail_values`, due to the missing `model` and `res_id` of the message.

This commit attaches the notification to the referrer's users instead, providing its `model` and `res_id`.

Reference
---------
opw-4943488

---

## [FIX] hr_referral: Do not send notif when opening the refuse wizard

Description
-----------
Currently, when opening the refusal wizard for an applicant, a call to `archive_applicant` is made. However, there is an override of it in `hr_referral` to send a notification for the applicant's refusal, and closing the `referral_state`, even though the applicant may have not been provided a reason for refusal, and the HR can simply close the wizard instead of confirming it.

This commit removes the override of `archive_applicant` and moves its logic into `action_refuse_reason_apply` which is called when the wizard is confirmed.

Reference
---------
opw-4943488

Forward-Port-Of: odoo/enterprise#90563
Forward-Port-Of: odoo/enterprise#90309