When /new or /reset is triggered, the session file gets rotated
before the hook runs. The hook was reading the new (empty) file
instead of the previous session content.
This fix:
1. Checks if the session file looks like a reset file (.reset.)
2. Falls back to finding the most recent non-reset .jsonl file
3. Logs debug info about which file was used
Fixesopenclaw/openclaw#18088