readStdinRaw() only settled on end, error or close. If the parent kept
stdin open without writing EOF, every hook that reads through it waited
until the harness killed it (an 8-10 s stall per call).
Add an idle deadline (default 3000 ms, ECC_HOOK_INPUT_IDLE_TIMEOUT_MS,
0 disables). It is reset on each chunk, unref()ed, and on expiry detaches
from and pauses the stream so a held-open pipe cannot keep the hook alive.
Input that already parses as a complete JSON object is accepted; anything
else is marked truncated so fail-closed safety hooks still block.
bash-hook-dispatcher.js now reads through the shared reader instead of its
own end/error-only loop.
Fixes#3665
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
