vscode-messenger

Implement and debug RPC messaging between a VS Code extension and its webviews using the `vscode-messenger` library. Use when wiring up extension–webview (or webview–webview) communication, defining `NotificationType` / `RequestType` message contracts, calling `sendRequest` / `sendNotification` / `onRequest` / `onNotification`, registering webviews with `Messenger`, sending to `HOST_EXTENSION` or `BROADCAST` participants, debugging why messages don't arrive, or setting up the `vscode-messenger-devtools` extension via `Messenger.diagnosticApi()`.