Phase A — Tamagosh-inspired redesign:
- Replace goroutine-based SSH (crypto/ssh) with tea.ExecProcess + native ssh binary
- Zero-lag SSH: native binary pegang TTY langsung, ga ada Go buffering
- Password auth via sshpass -e (SSHPASS env)
- Key auth via ssh -i <tmpfile> + SSH_ASKPASS for passphrase
- ControlMaster sockets for fast reconnect
- Add askpass subcommand for SSH_ASKPASS support
- Gruvbox Material Dark Hard palette for comfortable viewing
- Clean up old session messages (openSessionMsg, sessionOutputMsg, sessionDoneMsg)
- Remove 354-line session.go, replace with 150-line ssh.go