PeasyAI: stop converting named tuples to positional form #979

PCodePostProcessor converts named tuples such as:

(taskId = 42,)

to positional tuples:

(42,)

NamedTupleConstructionValidator then rejects the positional form and requires named fields. This causes valid generated code to fail validation, even though it compiles successfully.

Update Src/PeasyAI/src/core/compilation/p_post_processor.py to stop converting named tuples to positional form, and update the related tests.

Acceptance criteria

• Named tuple constructions remain unchanged during post-processing.
• NamedTupleConstructionValidator accepts valid named tuples.
• Existing validation tests pass.
• Add a regression test covering named tuple payloads in send and new.