feat: add list command with global filters

internal/output/plain.go

@@ -0,0 +1,28 @@
+package output
+
+import (
+	"fmt"
+	"io"
+)
+
+// plainFormatter emits one entry per line suitable for piping into other tools.
+type plainFormatter struct{}
+
+// NewPlainFormatter constructs a formatter for plain output.
+func NewPlainFormatter() Formatter {
+	return &plainFormatter{}
+}
+
+func (plainFormatter) Begin(io.Writer) error {
+	return nil
+}
+
+func (plainFormatter) WriteEntry(w io.Writer, entry Entry) error {
+	_, err := fmt.Fprintln(w, entry.Path)
+	return err
+}
+
+func (plainFormatter) WriteSummary(w io.Writer, summary Summary) error {
+	_, err := fmt.Fprintln(w, DefaultSummaryLine(summary))
+	return err
+}