update installation section in README

Added installation instructions for downloading binaries and building from source.

README.md

@@ -23,7 +23,28 @@ mikusays --help
 
 ## Installation
 
-build from source:
+### Download from [Releases](https://github.com/davideldios7/mikusays/releases):
+
+- **Windows**: `mikusays-*-windows.zip`
+- **Linux**: `mikusays-*-linux.tar.gz`
+- **macOS**: `mikusays-*-macos-*.tar.gz`
+
+Linux and macOS archives should preserve the executable permission. Extract and run one with:
+
+```bash
+tar -xzf "mikusays-VERSION"
+cd mikusays-VERSION
+./mikusays hi
+```
+
+The macOS binaries are unsigned. If Gatekeeper quarantines an extracted binary,
+remove the quarantine attribute before running it:
+
+```bash
+xattr -d com.apple.quarantine ./mikusays-VERSION-macos-arm64
+```
+
+or build from source:
 ```bash
 ./configure
 ```