Fix critical file selection and SSH connection issues in modern file manager

Major fixes that make the modern file manager fully functional:

🔧 Core Issues Fixed:
- File selection bug: All files showing as selected when only one was clicked
- SSH connection not established: 400 errors when loading directories
- File path undefined: Backend data missing proper path construction

🎯 File Selection Fix:
- Root cause: All file.path values were 'undefined', causing path comparison
  to always return true ('undefined' === 'undefined')
- Solution: Manually construct file paths from currentPath + fileName
- Result: Proper single/multi/range selection now works correctly

🔗 SSH Connection Enhancement:
- Added comprehensive connection status checking before operations
- Implemented automatic reconnection on connection failures
- Enhanced error handling with detailed logging and user feedback
- Added connection parameter validation and debugging

🛠️ Technical Improvements:
- Enhanced useFileSelection hook with safer state management
- Added extensive debugging logs for file operations and path construction
- Improved error messages and user feedback across all operations
- Robust file path building matching traditional file manager logic

The modern file manager now provides a fully functional, desktop-class
file management experience with proper selection, navigation, and operations.

src/ui/Desktop/Apps/File Manager/hooks/useFileSelection.ts

@@ -68,6 +68,11 @@ export function useFileSelection() {
     return selectedFiles.length;
   }, [selectedFiles]);
 
+  const setSelection = useCallback((files: FileItem[]) => {
+    console.log('Setting selection to:', files.map(f => f.name));
+    setSelectedFiles(files);
+  }, []);
+
   return {
     selectedFiles,
     selectFile,
@@ -77,6 +82,6 @@ export function useFileSelection() {
     toggleSelection,
     isSelected,
     getSelectedCount,
-    setSelectedFiles
+    setSelection
   };
 }