What & why

This pull request introduces stricter validation and improved UI logic for the "Transfer WIP Item" field on routing lines, ensuring that this field is only enabled and valid for "Work Center" type routing lines with subcontracting enabled. It also adds comprehensive automated UI and validation tests to guarantee correct behavior, and refactors some test utilities for better coverage and maintainability.

Validation and UI logic improvements:

• The "Transfer WIP Item" field is now only enabled and valid for routing lines of type "Work Center" with subcontracting enabled; it is disabled and validation fails for "Machine Center" types. [1] [2] [3]
• The "Transfer WIP Item" field is explicitly set as non-editable and invisible in the Subc. PO Subform page extension.

Automated test coverage:

• Added multiple UI and validation tests in Subc. Subcontracting UI Test to verify that the "Transfer WIP Item" field is only enabled for eligible Work Center lines and not for Machine Center lines, and that validation fails if incorrectly set.

Test utility enhancements:

• Introduced a new CreateRoutingLineForMachineCenter helper in the manufacturing management test library to streamline test setup for Machine Center routing lines, and made CreateRoutingLine public for broader utility. [1] [2]
• Added necessary codeunit references and error labels to support the new test scenarios. [1] [2]

Linked work

Fixes AB#640173

How I validated this

• I read the full diff and it contains only changes I intended.
• I built the affected app(s) locally with no new analyzer warnings.
• I ran the change in Business Central and confirmed it behaves as expected.
• I added or updated tests for the new behavior, or explained below why none are needed.

What I tested and the outcome (required — be specific: scenarios, commands, screenshots for UI changes)
Added Tests and do a manual validation in client

Risk & compatibility

None