The HR demo data now includes a corrected sample employee entry for Francis Laffineur, along with an associated employee image. This improves the realism and accuracy of demo environments used for presentations, testing, and onboarding.

@odony Improve hr demo data

Payroll users can now cancel a payslip and have its related accounting entry cancelled and removed in the same flow. This makes payslip corrections easier and aligns payroll handling with the familiar invoice cancellation process.

Allow cancel a payslip [ala invoice](https://github.com/odoo/odoo/blob/e05dba357ee44151db9449af4cfdf0d6c36d5dca/addons/account/models/account_invoice.py#L917-L935)
- Cancel account move (Previous validation of `allow cancel`)
- Delete account move (Like as account_invoice)

Stock package handling was simplified by removing an unnecessary hierarchy tracking mechanism. This reduces the chance of update conflicts and retries when package records are changed, improving reliability in stock operations without changing expected user workflows.

The model does not actually need this feature, as the hierarchies of packages
are not expected to be deep.  Performance wise, updating columns `parent_left`
and `parent_right` may actually suffer from concurrent updates that require
retrying requests.

This modification is motivated by issue #14493.