Add Mega-Debrid account info check (web scraping)

Scrapes the Mega-Debrid profile page to display username, premium status,
remaining days, and loyalty points. New "Account prüfen" button in Settings > Accounts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/shared/ipc.ts

@@ -36,5 +36,6 @@ export const IPC_CHANNELS = {
   EXTRACT_NOW: "queue:extract-now",
   GET_HISTORY: "history:get",
   CLEAR_HISTORY: "history:clear",
-  REMOVE_HISTORY_ENTRY: "history:remove-entry"
+  REMOVE_HISTORY_ENTRY: "history:remove-entry",
+  CHECK_ACCOUNT: "app:check-account"
 } as const;