fix(node:zlib): match modern constants table

[andrewtdiz]

Summary

• expose zlib.constants.ZLIB_VERNUM as a numeric constant
• stop exposing zlib.constants.Z_TREES, matching modern Node
• add granular parity coverage for the constants-table shape

Issue

• Part of Roadmap: Node.js + TypeScript compatibility & stability #793 (node:zlib module inventory parity)

Evidence

• Baseline exact node-suite/zlib/constants/modern-version-table: FAIL, test-parity/reports/parity_report_20260528_094351.json
• Final exact node-suite/zlib/constants/modern-version-table: PASS, test-parity/reports/parity_report_20260528_094542.json
• Full granular node-suite/zlib: PASS 47/47, test-parity/reports/parity_report_20260528_094630.json
• Broad top-level test_parity_zlib: still FAILS, test-parity/reports/parity_report_20260528_094717.json; residual diff is zstd APIs and zlib stream instance methods, not these constants
• cargo check -p perry-runtime -p perry-stdlib -p perry-codegen: PASS with existing warnings
• cargo fmt --check: PASS
• jq empty test-parity/known_failures.json: PASS
• git diff --check: PASS

DeepWiki

• reference/deepwiki/nodejs-node-zlib-modern-constants-2026-05-28.md

Non-goals

• no zstd codec implementation
• no zlib stream instance .close() / .params() / .reset() / .bytesWritten support
• no broad top-level zlib inventory cleanup
• no exact linked-zlib version emulation beyond exposing the numeric ZLIB_VERNUM surface