feat: comprehensive model management enhancements and platform fixes

- Block 1: Refactored path logic into a centralized PathResolver for OS-agnostic and relative path handling.
- Block 2: Improved platform compatibility (shutdown, macOS menu, System Tray fallback).
- Block 3: Added Power-User features (Model Updater, Smart Cleanup, Thumbnails, Node Sync, Remote Status).
- Fixes: Recursive subfolder scanning, archive detection logic, and UI progress throttling.

src/main/java/de/tki/comfymodels/service/IDownloadManager.java

@@ -10,4 +10,9 @@ public interface IDownloadManager {
     void togglePause();
     void stop();
     boolean isPaused();
+
+    /**
+     * Returns a map of current statuses for each model in the queue.
+     */
+    java.util.Map<Integer, String> getQueueStatus();
 }