Reorganize project into standard root layout

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

cmd/webterm/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/rcarmo/webterm-go-port/webterm"
+)
+
+func main() {
+	if err := webterm.RunCLI(os.Args[1:]); err != nil {
+		_, _ = fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}

cmd/webterm/main_test.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"os"
+	"testing"
+)
+
+func TestMainVersionFlag(t *testing.T) {
+	orig := os.Args
+	defer func() { os.Args = orig }()
+	os.Args = []string{"webterm", "-v"}
+	main()
+}