Add stdin fallback for diskpart when script file is virtualized/blocked

- Detect when script file disappears after successful creation
- Fall back to piping diskpart commands via stdin instead of script file
- Bypasses Windows security features that may block/virtualize temp files
- More reliable approach when file system access is restricted
- Addresses issue where file appears created but doesn't actually exist
- Resolves diskpart script access problems on secured Windows systems

usb_creator_gui.py

@@ -360,14 +360,26 @@ exit
         
         # Final verification before using the script
         if not os.path.exists(script_path):
-            raise Exception(f"Diskpart script was created but is no longer accessible at {script_path}")
+            self.status.emit(f"WARNING: Script file vanished after creation - {script_path}")
+            # Fall back to stdin approach if script file disappears
+            script_path = None
         
         try:
             # Run diskpart to format the USB drive
             self.status.emit("Formatting USB drive...")
+            
+            if script_path and os.path.exists(script_path):
+                # Use script file approach
+                self.status.emit(f"Using script file: {script_path}")
                 result = subprocess.run([
                     'diskpart', '/s', script_path
                 ], capture_output=True, text=True, timeout=60)
+            else:
+                # Fall back to stdin approach (more reliable)
+                self.status.emit("Using stdin approach (script file unavailable)")
+                result = subprocess.run([
+                    'diskpart'
+                ], input=diskpart_script, capture_output=True, text=True, timeout=60)
             
             # Clean up diskpart script
             try: