fix(stream): initialize duplex subclasses

[andrewtdiz]

Summary

• add a classic Duplex subclass init shim that installs Duplex methods and captures subclass _read/_write/_writev
• wire Duplex through generated default constructors and explicit super() lowering
• suppress Perry's fallback writable auto-echo only for Duplex instances with custom write sinks
• remove the stale known-failure entry for stream/subclass/extends-duplex

Verification

• ./run_parity_tests.sh --suite node-suite --module stream --filter node-suite/stream/subclass/extends-duplex
• ./run_parity_tests.sh --suite node-suite --module stream --filter node-suite/stream/subclass/ (Duplex/Readable pass; Transform remains listed; Writable also fails on clean current main)
• clean current-main probe: ./run_parity_tests.sh --suite node-suite --module stream --filter node-suite/stream/subclass/extends-writable (existing drift, report parity_report_20260529_163107.json)
• cargo check -p perry-runtime -p perry-codegen
• cargo fmt --all --check
• jq empty test-parity/known_failures.json
• git diff --check