release: prepare v2.0.43

Add sanitized provider and account runtime diagnostics, complete the Multi-Debrid-Downloader product rename, preserve existing application data during migration, update public release verification, and publish the accompanying English documentation and regression coverage.

src/main/realdebrid.ts

@@ -1,7 +1,7 @@
 import { API_BASE_URL, APP_VERSION, REQUEST_RETRIES } from "./constants";
 import { compactErrorText, sleep } from "./utils";
 
-const DEBRID_USER_AGENT = `RD-Node-Downloader/${APP_VERSION}`;
+const DEBRID_USER_AGENT = `MDD-Node-Downloader/${APP_VERSION}`;
 
 export interface UnrestrictedLink {
   fileName: string;