[bojemoi] fix(uzi): optimize meterpreter upgrade to survive ephemeral shell sessions

Commit `f3779a9`

Add upfront session liveness check before attempting upgrade
Try post/multi/manage/shell_to_meterpreter first (MSF native, ~30s max, no shell round-trips) before falling back to msfvenom+base64 injection
Pass _whoami from handle_new_sessions to upgrade_to_meterpreter to eliminate redundant whoami shell command (~9s saved)
Reduce shell_cmd timeout from 9s fixed to variable max_wait (5-9s)
Add session liveness check between strategy 1 and fallback
Refactor enrichment/reporting into _finalize_upgrade() helper

Previous flow took ~100s before first shell command, causing “Invalid session identifier” on ephemeral bind_netcat sessions.

Co-Authored-By: Claude Sonnet 4.6 noreply@anthropic.com