Expose protocol_id and session_id fields

[veljkovranic]

In ProveKit, while updating the recursive verifier, we need to access these values so that the Gnark circuit can initialize the nimue transcript with the same arguments WHIR uses.

[codspeed-hq]

Merging this PR will not alter performance

✅ 10 untouched benchmarks
⏩ 22 skipped benchmarks¹

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_{Comparing expose_session_and_protocol_id (13ee03f) with main (532aa71)}

Footnotes

1. 22 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩