feat: rebuild account management like JDownloader

Replace the grouped account cards with a viewport-filling 24px table, compact provider dialog, and separate usage rules view. Preserve account order and selections across bulk toggles, filtering, deletion, keyboard interaction, and narrow-window scrolling. Add focused regression coverage and publish the 2.0.9 changelog.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "real-debrid-downloader",
-  "version": "2.0.8",
+  "version": "2.0.9",
   "description": "Desktop downloader",
   "main": "build/main/main/main.js",
   "author": "Sucukdeluxe",