Currently, an error occurs when a user removes the payslip date.

**Steps to Reproduce:**

 - Install `l10n_hk_hr_payroll` with demo data.
 - Switch to the `Hong Kong` company.
 - Go to `Payroll` > `Payslips` > `Payslips`.
 - Create a `payslip` and remove the `start` or `end` period.

**Error 1:**
`TypeError: unsupported operand type(s) for +: 'bool' and 'relativedelta'`

**Error2:**
`AttributeError: 'bool' object has no attribute 'month'`

When a user removes the start or end date of a payslip, the system computes the Average Daily Wage. 
Based on the payslip dates, it finds the previous year's payslips [1]. If the start or end date is not set, 
it raises an error [2].
For the second error, when computing whether to include EOY pay, it compares the company's EOY 
pay date with the end date's month. If the end date is not set, accessing its month raises an error [3].

This commit ensures that when retrieving previous-year payslips, if the start or end date is not set, 
it returns an empty payslip recordset. It also ensures that when computing whether to include EOY 
pay, if the end date is not set, `include_eoy_pay` is set to `False`.

[1]: https://github.com/odoo/enterprise/blob/ec8a009794863090351d91650aff727e6fbeab7e/l10n_hk_hr_payroll/models/hr_payslip.py#L124

[2]- https://github.com/odoo/enterprise/blob/ec8a009794863090351d91650aff727e6fbeab7e/l10n_hk_hr_payroll/models/hr_payslip.py#L209-L215

[3]- https://github.com/odoo/enterprise/blob/ec8a009794863090351d91650aff727e6fbeab7e/l10n_hk_hr_payroll/models/hr_payslip.py#L141

## [FIX] industry_fsm_sale: fix invoice status for zero price lines

### Issue:
Without Anglo-Saxon accounting, the system incorrectly sets the invoice status of all zero price sales order lines linked to an FSM task to 'no'

This includes pre-existing lines that were already present on the quotation before confirmation. If a zero price line is pre-existing, it should follow the standard flow and be marked as 'to invoice'
Only lines added as materials from the field service task at a zero price should be considered included in the price and marked as 'no'

### Cause:
In `SaleOrderLine._compute_invoice_status`, the system forced `invoice_status = 'no'` for all zero price lines when Anglo-Saxon accounting was disabled
It failed to check if the lines were actually materials added via the FSM task or original quotation lines

### Fix:
A new `material_sale_lines` compute field is added to `project.task` to distinctly isolate and track lines added specifically as materials during the task execution

In `SaleOrderLine._compute_invoice_status`, the logic is updated to ensure that only zero price lines identified as FSM materials are set to 'no' when Anglo-Saxon accounting is disabled
Other pre-existing zero price lines properly remain as 'to invoice'

### Steps to reproduce:
- Install `industry_fsm_sale`
- In Settings > Users & Companies > Companies > Any company, add the field Anglo-Saxon using Studio (In 19.0+)
- Disable Anglo-Saxon on the current company
- Create a product Service (Fixed Price, that create a task in a Field Service Project)
- Create and confirm a Sale Order with the Service and one product with unit price 0
Before the fix, the pre-existing SO line with price 0 is 
incorrectly considered as not to invoice ('no')

opw-6169802

------------------------------

## [FIX] industry_fsm_sale: sync sale order invoice status

### Issue:
When a sale order contains FSM material lines with a price of zero and Anglo-Saxon accounting is disabled, the overall sale order invoice status remains stuck on 'to invoice' even after all other invoiceable lines are fully invoiced

### Cause:
The standard `SaleOrder._compute_invoice_status` does not handle FSM business rules regarding zero price material lines that are marked as `invoice_status = 'no'`
Because these lines are never technically invoiced, the global order status fails to transition to 'invoiced'

### Fix:
Override `SaleOrder._compute_invoice_status` to recompute the status of confirmed orders linked to FSM tasks

We use the task's `material_sale_lines` to filter out material components
If all lines on the order are either 'invoiced' or are zero price FSM material lines with Anglo-Saxon disabled, the global sale order status is forced to 'invoiced'

### Steps to reproduce:
- Install `industry_fsm_sale`
- In Settings > Users & Companies > Companies > Any company, add the field Anglo-Saxon using Studio (In 19.0+)
- Disable Anglo-Saxon on the current company
- Create a product Service (Fixed Price, that create a task in a Field Service Project)
- Create and confirm a Sale Order with the Service and one product with unit price 0
- Add a Product from the Task (Use a price 0 product, or set the unit price to 0 on the SO)
- Create the invoice for the Sale Order
Before the fix, the Service and Pre-existing product are invoiced, but in the Other Info Tab of the SO, the status stays on 'To Invoice' instead of 'Fully Invoiced'

opw-6169802

Steps to reproduce:
---------------------------------------
1. Install Subscription Module
2. Create and Confirm SO with no recurring plan and a non-recurring product
3. Add a recurring product > Save SO > Observe the User Error
4. Now add the same recurring product through Catalog View

Observation:
---------------------------------------
No User Error raised stating
'You cannot save a sale order with recurring product and no subscription plan.'

Issue:
---------------------------------------
When you manually add a line and click 'Save', the constraint (`_constraint_subscription_plan`) is triggered and raised `UserError` https://github.com/odoo/enterprise/blob/434d88960abb5e424fdc1106fc93935d328bff78/sale_subscription/models/sale_order.py#L176-L177

When you add a product via the catalog view, it calls `_update_order_line_info` which directly creates/updates order lines, Which do not trigger the python constraint.
https://github.com/odoo/odoo/blob/ef9772bba1515bdaf5410c3af5a3e395f562d513/addons/sale/models/sale_order.py#L1926-L1933

Solution:
---------------------------------------
Two private helpers are introduced:
* `_is_exempt_from_subscription_plan_check`: single source of truth for all exempt states (draft, cancelled, upsell, and legacy upgrade orders).
* `_check_recurring_plan_mismatch`: raises a `UserError` when the order has or will have a recurring product but no subscription plan, reusing the exemption helper so both call sites stay in sync.

`_constraint_subscription_plan` is refactored to delegate to these helpers, and `_update_order_line_info` is overridden to call `_check_recurring_plan_mismatch` before the catalog update is applied, ensuring consistent validation across both entry points.

opw-6194865

Forward-Port-Of: odoo/enterprise#122253
Forward-Port-Of: odoo/enterprise#117879

Steps to reproduce:
1. Install eCommerce and Subscriptions.
2. Create a 21% Excluded tax.
3. Create a subscription product with a price of 45 with 21% tax and enable "Accept One-Time" in the Recurring Prices tab.
4. Publish the product on the website under the Sales tab.
5. Create a pricelist for 6 months recurring with two lines:
 - If min quantity is 0, then 0% discount
 - If min quantity is 2, then 5% discount
6. Set "Display Product Prices" to "Tax Included" in the Settings.
7. Open the product on the website, select the 6-month plan, and increase quantity to 2.

Issue:
The discount percentage displayed on the website shows 4% instead of the configured 5%.

Why this happens:
In `_get_additionnal_combination_info`, the discount is reverse-calculated from the tax-included price vs the tax-included sales price. When the 21% tax is included to both prices, it introduces a floating-point precision loss (4.9954..%), which floor() then truncates to 4%.

Fix:
When the pricelist rule uses 'percentage' discount, read `percent_price` directly from the pricing rule instead of reverse-calculating from tax-adjusted prices, as it represents the exact discount percentage the merchant configured with no floating-point involvement.

opw-6224735