Get communication working between extension and webview; add shared data types

webview-ui/src/utilities/vscode.ts

@@ -1,3 +1,4 @@
+import { WebviewMessage } from "@shared/WebviewMessage"
 import type { WebviewApi } from "vscode-webview"
 
 /**
@@ -28,7 +29,7 @@ class VSCodeAPIWrapper {
 	 *
 	 * @param message Abitrary data (must be JSON serializable) to send to the extension context.
 	 */
-	public postMessage(message: unknown) {
+	public postMessage(message: WebviewMessage) {
 		if (this.vsCodeApi) {
 			this.vsCodeApi.postMessage(message)
 		} else {