refactor(tui): use strconv.Atoi in parseIntClamp, drop spurious error return

internal/tui/wizard/wizard.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"strconv"
 	"strings"
 
 	"github.com/charmbracelet/huh"
@@ -88,12 +89,13 @@ func Run(ctx context.Context, reg *module.Registry, initial tui.WizardState) (tu
 		return s, false, err
 	}
 
+	// Redundant-but-safe: the DescriptionFunc closure on the plan-review
+	// screen already kept s.Modules in sync. The MultiSelect group is
+	// frozen by the time we reach here, so this is idempotent. Kept for
+	// the case where the form is exited via a path that bypasses the
+	// plan-review screen in future revisions.
 	s.Modules = syncSelected(s.Modules, selectedModules)
-	// Parse parallelism: clamp to 1 on any parse failure, since the wizard
-	// uses a free-form Input; a stricter schema can come later.
-	if n, perr := parseIntClamp(parallelismStr, 1); perr == nil {
-		s.Parallelism = n
-	}
+	s.Parallelism = parseIntClamp(parallelismStr, 1)
 	s.Confirmed = proceed
 	return s, proceed, nil
 }
@@ -149,15 +151,18 @@ func renderPlan(ctx context.Context, reg *module.Registry, selectedIDs []string)
 	return b.String()
 }
 
-// parseIntClamp parses s as int. Empty or invalid input returns fallback.
-func parseIntClamp(s string, fallback int) (int, error) {
+// parseIntClamp parses s as a positive int. Empty, non-numeric (including
+// partial matches like "3abc"), negative, zero, or overflowing input all
+// return fallback. strconv.Atoi (not fmt.Sscanf) is used so partial matches
+// are rejected and overflow surfaces as an error.
+func parseIntClamp(s string, fallback int) int {
 	s = strings.TrimSpace(s)
 	if s == "" {
-		return fallback, nil
+		return fallback
 	}
-	var n int
-	if _, err := fmt.Sscanf(s, "%d", &n); err != nil || n < 1 {
-		return fallback, nil
+	n, err := strconv.Atoi(s)
+	if err != nil || n < 1 {
+		return fallback
 	}
-	return n, nil
+	return n
 }

internal/tui/wizard/wizard_test.go

@@ -48,13 +48,15 @@ func TestParseIntClamp(t *testing.T) {
 		"":     1,
 		"  ":   1,
 		"abc":  1,
+		"3abc": 1, // partial match is rejected (strconv.Atoi, not Sscanf)
 		"0":    1,
 		"-5":   1,
 		"3":    3,
 		"12":   12,
+		"99999999999999999999": 1, // overflow → fallback
 	}
 	for in, want := range cases {
-		got, _ := parseIntClamp(in, 1)
+		got := parseIntClamp(in, 1)
 		if got != want {
 			t.Errorf("parseIntClamp(%q) = %d, want %d", in, got, want)
 		}