--input-format stream-json: no output and wrong exit code (the SDK entry point silently succeeds with nothing)

[proggeramlug]

echo '{"type":"user","message":{...}}' | claude -p --input-format stream-json --output-format stream-json --verbose
  node : rc=1, 2633 bytes  (system/init, assistant, result records)
  perry: rc=0, 0 bytes

This is the programmatic/SDK entry point for driving claude-code, and under perry it emits nothing and reports success. Anything scripted against it sees a clean exit and an empty stream.

Found by a differential stress-test of cc 2.1.112 under perry 757beace0 vs node on the identical bundle; raw pairs at /root/claude-ccstress/out/.

[proggeramlug]

Closing: fixed in #9407.