[FEATURE] Support keybindings.json (or a native toggle) in the desktop app's embedded chat input

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

The ~/.claude/keybindings.json system documented at https://code.claude.com/docs/en/keybindings only applies to the terminal-based (ink) renderer. It has no effect on the embedded chat input inside the Claude desktop app (the chat surface that talks to the claude subprocess via --output-format stream-json).

Proposed Solution

Feature request: either (a) make the desktop app's chat input respect keybindings.json (specifically chat:submit / chat:newline), or (b) add a native app setting to choose the send shortcut (e.g. "Send with ⌥+Enter / Ctrl+Enter" vs. "Send with Enter"), similar to what Slack/Discord offer.

This would let users who prefer Enter-for-newline / modifier-for-send workflows use that consistently across both the terminal CLI and the desktop app.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_