fix: ensure the theme store triggers the cloud sync upon install

src/background.ts

@@ -5,6 +5,7 @@ import {
   initCloudSettingsAutoSync,
   performCloudSettingsDownloadWithRetry,
   performCloudSettingsUploadWithRetry,
+  requestCloudSettingsDebouncedUpload,
   runCloudSettingsPoll,
 } from "./background/cloudSettingsAutoSync";
 
@@ -346,6 +347,10 @@ const MESSAGE_HANDLERS: Record<string, MessageHandler> = {
     void runCloudSettingsPoll();
     return false;
   },
+  cloudSettingsRequestDebouncedUpload: () => {
+    requestCloudSettingsDebouncedUpload();
+    return false;
+  },
   getSeqtaSession: (req: { baseUrl?: string }, sendResponse: MessageSender, sender?: browser.Runtime.MessageSender) => {
     (async () => {
       try {