v2.3.0 — Copilot CLI-style UI

What's new in v2.3.0

Copilot CLI-style interactive UI

• Bordered panels (src/ui/box.ts): GitHub Copilot CLI-style ╭─ title ─╮ panel renderer with default, command, and response styles; commandChip() for styled command display
• Interactive /suggest (src/commands/suggest-cmd.ts): full shell-picker flow (auto-detects bash/zsh/fish/powershell/cmd), streams command generation, then presents an execute / copy / explain / revise action loop
• Streaming syntax highlight (src/ui/render.ts): StreamSink detects fenced code blocks across token boundaries and applies shell-aware syntax highlighting in real time; boxResponse() renders markdown AI responses inside a bordered panel
• TUI busy indicator (src/modes/tui.ts): thinking separator, ◆ busy prompt icon, /suggest hint in status line