- Use last-8 chars of transcript UUID instead of first-8, matching
getSessionIdShort()'s .slice(-8) convention. Same session now produces the
same filename whether shortId comes from CLAUDE_SESSION_ID or transcript_path,
so existing .tmp files are not orphaned on upgrade.
- Normalize extracted hex prefix to lowercase to avoid case-driven filename
divergence from sanitizeSessionId()'s lowercase output.
- Explicitly clear CLAUDE_SESSION_ID in the first regression test so the env
leak from parent test runs cannot hide the fallback path.
- Add regression tests for the lowercase-normalization path and for the case
where CLAUDE_SESSION_ID and transcript_path refer to the same UUID (backward
compat guarantee).
Refs #1494
93cd5f4cff