feat: output system — table/json/yaml/raw printers with struct tag driven tables

internal/output/output.go

@@ -0,0 +1,33 @@
+package output
+
+import (
+	"fmt"
+	"io"
+)
+
+type Printer struct {
+	format string
+	writer io.Writer
+}
+
+func New(format string, w io.Writer) *Printer {
+	return &Printer{format: format, writer: w}
+}
+
+func (p *Printer) Print(data any) error {
+	switch p.format {
+	case "table":
+		return printTable(p.writer, data)
+	case "json":
+		return printJSON(p.writer, data)
+	case "yaml":
+		return printYAML(p.writer, data)
+	default:
+		return fmt.Errorf("unknown output format: %s", p.format)
+	}
+}
+
+func (p *Printer) PrintRaw(raw []byte) error {
+	_, err := fmt.Fprintln(p.writer, string(raw))
+	return err
+}