Update README with features and requirements

Expanded the README to include a project description, feature list, and system requirements. Clarifies that the application is Windows-only and details its functionality.

Author: Polish-Coder

README.md

@@ -1,4 +1,10 @@
 # Disc Viewer
- 
-### Author:
-- Polish Coder
+A console application to display folder and file sizes based on actual disk usage.
+
+## Features
+- Shows total size of the specified folder.
+- Lists immediate subfolders and files.
+- Calculates the real disk space used by files.
+
+## Requirements
+- Operating System: **Windows only** (uses Windows API).