feat(extension): migrate chrome extension v2 to v3

extensions/chrome/src/bg/service-worker.js

@@ -0,0 +1,12 @@
+// This is the service worker script, which executes in its own context
+// when the extension is installed or refreshed (or when you access its console).
+// It would correspond to the background script in chrome extensions v2.
+
+console.log("This prints to the console of the service worker (background script)");
+chrome.runtime.onMessage.addListener(
+    function(request, sender, sendResponse) {
+        if (request.msg === "sendMessage") {
+        sendResponse({response: "Message received"});
+        }
+    }
+);