fix(runner): recognize MINGW/MSYS/CYGWIN as Windows in wrapper script

The Unix wrapper script now properly detects Git Bash, MSYS2, and Cygwin
environments as Windows and uses the correct Windows binary with .exe
extension.

Closes #45

Author: CalvinAllen

DESIGN.md

@@ -68,9 +68,11 @@ set -e
 
 # Detect OS
 OS=$(uname -s | tr '[:upper:]' '[:lower:]')
+EXT=""
 case "$OS" in
   linux*) OS="linux" ;;
   darwin*) OS="macos" ;;
+  mingw*|msys*|cygwin*) OS="windows"; EXT=".exe" ;;
   *) echo "Error: Unsupported OS: $OS" >&2; exit 1 ;;
 esac
 
@@ -82,7 +84,7 @@ case "$ARCH" in
   *) echo "Error: Unsupported architecture: $ARCH" >&2; exit 1 ;;
 esac
 
-BINARY="$(dirname "$0")/.rnr/bin/rnr-${OS}-${ARCH}"
+BINARY="$(dirname "$0")/.rnr/bin/rnr-${OS}-${ARCH}${EXT}"
 
 if [ ! -f "$BINARY" ]; then
   echo "Error: rnr is not configured for ${OS}-${ARCH}." >&2

src/commands/init.rs

@@ -264,9 +264,11 @@ set -e
 
 # Detect OS
 OS=$(uname -s | tr '[:upper:]' '[:lower:]')
+EXT=""
 case "$OS" in
   linux*) OS="linux" ;;
   darwin*) OS="macos" ;;
+  mingw*|msys*|cygwin*) OS="windows"; EXT=".exe" ;;
   *) echo "Error: Unsupported OS: $OS" >&2; exit 1 ;;
 esac
 
@@ -278,7 +280,7 @@ case "$ARCH" in
   *) echo "Error: Unsupported architecture: $ARCH" >&2; exit 1 ;;
 esac
 
-BINARY="$(dirname "$0")/.rnr/bin/rnr-${OS}-${ARCH}"
+BINARY="$(dirname "$0")/.rnr/bin/rnr-${OS}-${ARCH}${EXT}"
 
 if [ ! -f "$BINARY" ]; then
   echo "Error: rnr is not configured for ${OS}-${ARCH}." >&2