- Modified chatwin_outgoing_msg to call _chatwin_set_last_message for corrected messages, using replace_id per XEP-0308.
- Updated _chatwin_set_last_message to skip redundant and invalid free/strdup for same pointers.
- Added null checks in _chatwin_set_last_message for safety.
- Fixes autocompletion suggesting original message content instead of corrected content.
Fixes#24