Update changelog.md for version 0.0.401

Author: github-actions[bot]

changelog.md

@@ -1,3 +1,19 @@
+## 0.0.401 - 2026-02-03
+
+- Support `.agents/skills` directory for auto-loading skills
+- Improve handling of chat history when switching between model families
+- MCP tools returning structuredContent now display correctly in CLI
+- Support Claude-style .mcp.json format without mcpServers wrapper
+- Inserting new line with shift+enter keybinding in VS Code integrated terminal
+- Large multi-line pastes work correctly
+- ACP terminal-auth passes correct arguments to login
+- Arrow and special keys work reliably when held down
+- Slash command ghost text appends correctly
+- Add `copilot login` subcommand and support ACP terminal-auth
+- Add agentStop and subagentStop hooks to control agent completion
+- CLI handles unknown keypresses gracefully
+- /diff displays accurate line numbers with dual column layout
+
 ## 0.0.400 - 2026-01-30
 
 - Add MCP server instructions support