docs: transient_options.md lists tran_itl as not implemented but it is fully implemented

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Problem

transient_options.md has a table of "Not Yet Implemented" options that incorrectly lists tran_itl:

tran_itl | ❌ | Max NR iterations per step

Reality

tran_itl is fully implemented:

• vajax/analysis/options.py: defines tran_itl: int = 20 with validation
• vajax/analysis/transient/full_mna.py: uses config.tran_itl as max_iterations in the NR loop

This is the same class of bug as #112 (tran_ft incorrectly listed as not implemented).