[anthonymontebrun]

Checklist before requesting a review

• I have performed a self-review of my code.
• I have added tests (when available) that prove my fix is effective or that my feature works.
• I have updated the CHANGELOG with a short functional description of the fix or new feature.

Description

This PR adds two options on each credit voucher, Usable for incidents and Usable for requests, to control the ticket types on which the voucher can be consumed. Both options are enabled by default, so existing behaviour is unchanged.

Voucher configuration

• New fields is_for_incidents / is_for_requests on glpi_plugin_credit_entities (default 1). They are available in the entity tab add form, in the voucher form, in the vouchers list and as search options (998 / 999).
• Migration adds both columns and sets existing vouchers to 1. Running it again is safe.

Ticket side

• The voucher dropdowns only list vouchers usable for the ticket type: the followup / task / solution consume block, the ticket Credit tab and the ticket default vouchers.
• The "Consume a voucher?" block is hidden when the entity has no active voucher usable for the ticket type.
• A default voucher (ticket or entity level) that does not match the ticket type is not preselected.

Enforcement

• PluginCreditTicket::prepareInputForAdd() / prepareInputForUpdate() reject a consumption whose voucher cannot be used for the ticket type. This covers the followup / task / solution hook, the ticket tab, the "Update" massive action and the API. On update, the check only runs when the ticket or the voucher changes, so editing the quantity of an older consumption still works.
• PluginCreditTicketConfig resets a ticket default voucher that does not match the ticket type, and shows a warning. This applies both from the ticket form, which uses the type submitted in the same form, and from the ticket tab.

Tests

• tests/Units/TicketTypeVoucherTest.php:
  • default values
  • consumption rejected or accepted depending on the ticket type
  • consumption cannot be added or moved to a voucher that does not match the ticket type
  • an invalid ticket default voucher is reset
  • the consume block is shown or hidden depending on the vouchers available.