Turbopack: handle webpack loader event backpressure (#78462)
## Improve IPC socket handling in Turbopack Node.js communication
### What?
Enhances the IPC communication between Turbopack and Node.js processes
by implementing proper socket backpressure handling.
### Why?
The current implementation doesn't properly handle backpressure when
writing to sockets, which can lead to hanging where Node.js doesn't
write the rest of the data.
### How?
- Added a `Writable` stream wrapper around the socket to properly handle
backpressure
- Implemented drain event handling to ensure data is written correctly
- Enabled noDelay on both the Node.js client and Rust server sides
- Moved stringify into the promise to make the stringify + write happen
in the same tick.
Part of PACK-4409
Fixes #78407
