feat(v0.4): add ConfirmYN prompt helper

internal/session/prompt.go

@@ -0,0 +1,32 @@
+package session
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// ConfirmYN prints prompt to out, reads one line from in, and returns:
+//   - true for "y"/"yes" (case-insensitive)
+//   - false for "n"/"no" (case-insensitive)
+//   - defaultYes for empty input
+//   - !defaultYes for any other input (treat unrecognized as the
+//     opposite of the default, i.e., the safer choice given the default)
+func ConfirmYN(in io.Reader, out io.Writer, prompt string, defaultYes bool) bool {
+	fmt.Fprint(out, prompt)
+	reader := bufio.NewReader(in)
+	line, _ := reader.ReadString('\n')
+	answer := strings.TrimSpace(strings.ToLower(line))
+
+	if answer == "" {
+		return defaultYes
+	}
+	if answer == "y" || answer == "yes" {
+		return true
+	}
+	if answer == "n" || answer == "no" {
+		return false
+	}
+	return !defaultYes
+}