VS Code extension: register /btw slash command in thin-client registry

Summary

The /btw slash command (Ask a quick side question without interrupting the main conversation) exists in the CLI but is not registered in the VS Code extension's thin-client command registry, so it does not appear in autocomplete or run when typed.

Repro

• CLI version: 2.1.173 (Mac arm64)
• VS Code extension version: 2.1.173 (anthropic.claude-code-2.1.173-darwin-arm64)
• In a VS Code Claude Code session, type /btw <question> — the command does not appear in the slash-command picker and is not dispatched.

Evidence

In the CLI binary, the command is registered with:

{
  name: "btw",
  description: "Ask a quick side question without interrupting the main conversation",
  immediate: true,
  argumentHint: "<question>",
  thinClientDispatch: "control-request"
}

The thinClientDispatch: "control-request" field indicates this command is designed to be dispatched from a thin client (like the VS Code extension) via a control request. However, the extension's bundled extension.js contains zero references to "btw", so the thin client doesn't list it among its slash commands.

Request

Please add /btw to the VS Code extension's slash-command registry so it surfaces in autocomplete and dispatches the control request to the underlying session.

Environment

• OS: macOS (darwin 25.5.0, arm64)
• VS Code extension: anthropic.claude-code-2.1.173-darwin-arm64
• CLI: 2.1.173