Reintegrate TypeScript compatibility fixes for P2 and P3

[noise64]

• supersedes TS compat fixes based on reported lib compatibility issues #120 by reintegrating its TypeScript compatibility work on current main with explicit Preview 2 and Preview 3 coverage
• enables fatal TextDecoder / TextDecoderStream behavior and stateful split-sequence decoding for UTF and legacy multibyte encodings
• fixes Request / Response body cloning, exact BufferSource ranges, construction-time snapshots, and the real @openrouter/sdk 0.12.35 request path
• supports ordered WebSocket and WebSocketStream binary/Blob sends, snapshots mutable queued data, and drains accepted frames before close
• propagates fetch aborts to native request, upload, and redirect work while waiting for response headers, and preserves standard post-abort response-body errors
• adds P2/P3 runtime regressions, generated DTS goldens, and current-toolchain Rust/TypeScript lint fixes
• tracks GOL-60, GOL-223, GOL-324, GOL-325, GOL-346, GOL-353, GOL-354, and GOL-356
• follow-up: GOL-404 covers P3 resolve-after-headers, lazy response-body ownership, and abort during pending or cloned/shared body reads

Node compatibility

• primary CI-enforced: 3239/4425 (73.2%) → 3228/4425 (72.9%)
• full public: 3239/5750 (56.3%) → 3228/5750 (56.1%)
• the honest passing count decreases by 11: the implemented fatal and stateful decoder behavior has P2/P3 runtime coverage, but the split upstream TextDecoder fixture assumes common.hasIntl=false requires fatal construction to throw ERR_NO_ICU; setting common.hasIntl=true would falsely claim broader Intl/ICU and IDNA compatibility