hermes - 💡(How to fix) Fix TUI: Shift+Enter and Alt+Enter both submit instead of inserting newline in Warp terminal

Issue

In the Hermes TUI (prompt_toolkit-based CLI), both Shift+Enter and Alt+Enter submit the message instead of inserting a newline for multi-line input when using Warp terminal.

Expected behavior

• Shift+Enter -> insert newline (standard terminal/chat convention)
• Alt+Enter -> insert newline (documented Hermes keybinding per line 4880 of cli.py)
• Enter -> submit

Actual behavior

Both Shift+Enter and Alt+Enter behave like Enter - they submit the message immediately. The only workaround is pressing Escape then Enter sequentially.

Environment

• Terminal: Warp (latest)
• Hermes: latest main
• OS: Linux (OrbStack container on macOS)

Notes

This works fine in other terminals (iTerm2, built-in Terminal) where Alt+Enter is properly passed through as an escape sequence. Warp appears to handle modifier keys differently, so Shift+Enter support would be a more universal solution and matches the convention used by most terminal apps and chat UIs.

Suggested fix: Add a s-enter keybinding in cli.py that inserts a newline, alongside the existing Alt+Enter binding.