Wrap json.loads() in load_transcript() with try/except JSONDecodeError
so that partial JSONL lines (from mid-write crashes like OOM/SIGKILL)
are skipped with a warning instead of crashing the entire transcript
load. The rest of the history loads fine.
Adds a logger.warning with the session ID and truncated corrupt line
content for debugging visibility.
Salvaged from PR #1193 by alireza78a.
Closes#1193