Separate pause/resume buttons, fix hybrid extraction during pause

- Pause button is now one-way (orange glow when paused, disabled when
  already paused). Start button resumes from pause.
- Fix hybrid extraction attempting incomplete multi-part archives when
  paused: disk-fallback now blocks any non-terminal item status, not
  just downloading/validating/integrity_check.

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "real-debrid-downloader",
-  "version": "1.5.1",
+  "version": "1.5.11",
   "description": "Real-Debrid Downloader Desktop (Electron + React + TypeScript)",
   "main": "build/main/main/main.js",
   "author": "Sucukdeluxe",