Add item-recovery for stuck downloads with completed files on disk

When post-processing runs, detect items in idle states (queued/paused)
whose target file already exists on disk with non-zero size, and
auto-recover them to "completed" status. This ensures allDone becomes
true, triggering final extraction with archive cleanup (delete mode).

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "real-debrid-downloader",
-  "version": "1.4.77",
+  "version": "1.4.78",
   "description": "Real-Debrid Downloader Desktop (Electron + React + TypeScript)",
   "main": "build/main/main/main.js",
   "author": "Sucukdeluxe",