Bun tightens streams, buffer, and HTTP fixes

ReadableStream internals get refactored to avoid closure leaks (a830e9d)

Bun extracts several long-lived ReadableStream callbacks into top-level builtins and binds their state explicitly, so stored pull/cancel/start handlers no longer capture an entire setup activation. This should reduce retained memory and makes stream controller lifetimes closer to the spec’s intended shape.

Node:http drain callback no longer panics when onWritable is cleared (942c222)

The server response path now checks for a cleared onwritable slot before scheduling drain callbacks, and it stops resetting the cached slot to undefined in a way that could contribute to stale state. A new regression test covers the crash scenario where drain fires after the slot has already been cleared.

Buffer error behavior is brought closer to Node (dd13155)

This update syncs the vendored node:buffer suite to Node v26.3.0 and includes compatibility fixes in the Buffer/error-code paths. Notably, out-of-range reads now preserve Node’s Infinity handling and large numeric/bigint values are formatted with numeric separators in range errors, improving test parity and developer-facing error messages.

Other misc changes

• Streams typing/docs example updated to typecheck under number | Promise<number> backpressure returns (15bc359)
• Small internal cast/instance checks in bindings.cpp and process argument validation (6a574c4)
• CLAUDE.md guidance updated to keep code comments to 3 lines max (f91c27b)