- Add normalizeDeliveryTarget helper to strip user:/chat: prefixes for Feishu
- Apply normalization in matchesMessagingToolDeliveryTarget before comparison
- This ensures cron duplicate suppression works when session uses prefixed targets
(user:ou_xxx) but messaging tool extract uses normalized bare IDs (ou_xxx)
Fixes review comment on PR #32755
(cherry picked from commit fc20106f16)