fix: add missing cmd/shush/main.go and update gitignore

cmd/shush/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/alecthomas/kong"
+	"github.com/carlosarraes/shush/internal/processor"
+	"github.com/carlosarraes/shush/internal/types"
+)
+
+var version = "0.1.0"
+
+func main() {
+	var cli types.CLI
+	kong.Parse(&cli, 
+		kong.Description("Remove comments from source code files"),
+		kong.Vars{"version": version})
+
+	if cli.Path == "" {
+		fmt.Fprintf(os.Stderr, "Error: path argument is required\n")
+		os.Exit(1)
+	}
+
+	if cli.Inline && cli.Block {
+		fmt.Fprintf(os.Stderr, "Error: --inline and --block flags are mutually exclusive\n")
+		os.Exit(1)
+	}
+
+	proc := processor.New(cli)
+	if err := proc.Process(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+}