* Fix#3409: Add fallback to session_search to prevent false negatives on summarization failure
Fixes#3409. When the auxiliary summarizer fails or returns None, the tool now returns a raw fallback preview of the matched session instead of silently dropping it and returning an empty list
* fix: clean up fallback logic — separate exception handling from preview
Restructure the loop: handle exceptions first (log + nullify), build
entry dict once, then branch on result truthiness. Removes duplicated
field assignments and makes the control flow linear.
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Co-authored-by: devorun <130918800+devorun@users.noreply.github.com>