Add keybinding action for clear/new chat

Feature Request

Add a keybinding action to clear the current chat or start a new chat session.

Problem

Currently, there is no keybinding action available for the /clear command. Users cannot bind a keyboard shortcut (e.g., Ctrl+N) to quickly start a fresh conversation.

Proposed Solution

Add following actions:

• chat:clear in the Chat context
• other:menu:items in the Global/Chat context

This would allow users to configure keybindings like:

{
  "bindings": [
    {
      "context": "Chat",
      "bindings": {
        "ctrl+n": "chat:clear"
      }
    }
  ]
}

Use Case

Quickly starting a new conversation is a common workflow. Having a keyboard shortcut for this (similar to Ctrl+N in many applications) would improve productivity.