Enhance README with download and support information

Added sections for download options, auto-updates, and issue reporting.

Author: inureyes

README.md

@@ -1,2 +1,19 @@
-# backend.ai-go-releases
 This repository hosts official releases of Backend.AI GO.
+
+## Download
+
+Download the latest version for your platform from the [Releases](../../releases) page.
+
+| Platform | File |
+|----------|------|
+| macOS (Apple Silicon) | `backend.ai-go-x.x.x-macos-arm64.dmg` |
+| Windows | `backend.ai-go-x.x.x-windows-x64-setup.exe` |
+| Linux | `backend-ai-go-x.x.x-linux-x64.deb` |
+
+## Auto-Updates
+
+The application automatically checks for updates on startup. You can also manually check via Settings → Check for Updates.
+
+## Reporting Issues
+
+We are preparing discussion channel for the bug reports and feature requests.