4: Make visitor immutable friendly #253

Performance Gate Passed

✅ 14 untouched benchmarks
🆕 4 new benchmarks

	Benchmark	`BASE`	`HEAD`	Efficiency
🆕	`test_pickle_large_query_decode`	N/A	207.8 ms	N/A
🆕	`test_parse_large_query`	N/A	421.4 ms	N/A
🆕	`test_pickle_large_query_roundtrip`	N/A	317.3 ms	N/A
🆕	`test_pickle_large_query_encode`	N/A	109.8 ms	N/A

_{Comparing corydolphin:make-visitor-immutable-friendly (c63ef1d) with main (283d002)}