Get Session Results

Public endpoint — returns interview summary/results for the interviewee to see after the session ends. No auth required (session_id is the auth, same as the join endpoint).

NOTE: This is the OLDER of two duplicate definitions of this route — the newer one above (line ~2581) handles revision-correctness. Because both register the same path, FastAPI uses this one (the last @router.get wins). Deduplication is deferred to its own PR; see CHOICES.md.