[FEATURE] newContect mappable action

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

recently, ctrl+l ctrl+l used to create a new context. now, ctrl+l redraws the screen. this action does not seem to be remappable. The feature of the keybind for making a new context on the fly was removed.

Proposed Solution

add this as a chat context binding. allowing the user to do something like this:

``` json
"bindings": [
{
"context": "Chat",
"bindings": {
"ctrl+e": "chat:externalEditor",
"ctrl+f": "chat:modelPicker",
"ctrl+j": "chat:newline",
"ctrl+n": "chat:newContext" <- here
}
}
]

### Alternative Solutions

_No response_

### Priority

High - Significant impact on productivity

### Feature Category

Configuration and settings

### Use Case Example

_No response_

### Additional Context

_No response_