## Summary
Fixes two critical bugs in Bun Shell:
1. **Memory leaks & incorrect GC reporting**: Shell objects weren't
reporting their memory usage to JavaScriptCore's garbage collector,
causing memory to accumulate unchecked. Also fixes a leak where
`ShellArgs` wasn't being freed in `Interpreter.finalize()`.
2. **Blocking I/O on macOS**: Fixes a bug where writing large amounts of
data (>1MB) to pipes would block the main thread on macOS. The issue:
`sendto()` with `MSG_NOWAIT` flag blocks on macOS despite the flag, so
we now avoid the socket fast path unless the socket is already
non-blocking.
## Changes
- Adds `memoryCost()` and `estimatedSize()` implementations across shell
AST nodes, interpreter, and I/O structures
- Reports estimated memory size to JavaScriptCore GC via
`vm.heap.reportExtraMemoryAllocated()`
- Fixes missing `this.args.deinit()` call in interpreter finalization
- Fixes `BabyList.memoryCost()` to return bytes, not element count
- Conditionally uses socket fast path in IOWriter based on platform and
socket state
## Test plan
- [x] New test: `shell-leak-args.test.ts` - validates memory doesn't
leak during parsing/execution
- [x] New test: `shell-blocking-pipe.test.ts` - validates large pipe
writes don't block the main thread
- [x] Existing shell tests pass
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Replace `catch bun.outOfMemory()`, which can accidentally catch
non-OOM-related errors, with either `bun.handleOom` or a manual `catch
|err| switch (err)`.
(For internal tracking: fixes STAB-1070)
---------
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
