Say a signal or timeout mid-request leaves no stopped record

A SIGINT while agent investigate waits on the model exits 130 with no
investigation record: treaty defers closing the stream until the
handler's next() returns, and the process exits first. The CHANGELOG
said such a run is recorded stopped.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: shipmill-romamo[bot]

CHANGELOG.md

@@ -413,9 +413,10 @@ Notable changes to Cloudfall. The format follows
   them, and exited 0. The record is now saved ended `stopped`, a new status
   in `agent-investigation.schema.json`, with the steps, turns and tokens so
   far, an empty `answer` and no `finding`; nothing more is written to the
-  closed stdout, and the command exits 94 `INVESTIGATION_STOPPED`. A stream
-  stopped by a signal or a timeout is recorded `stopped` too and keeps its
-  own exit code; `--no-stream` is unchanged (#44)
+  closed stdout, and the command exits 94 `INVESTIGATION_STOPPED`. A run
+  stopped by a signal or a timeout keeps its own exit code, and one stopped
+  while it waits on the model still leaves no record;
+  `--no-stream` is unchanged (#44)
 - The operator proposal schema refuses `approval.via` on an autonomous
   (policy) approval. Such a receipt used to pass validation and lose the
   field on load; it now fails schema validation like any other invalid