fix(lint): resolve goconst and shadow lint errors

- Add boolTrue/boolFalse constants for string "true"/"false" values
- Rename shadowed err variable to writeErr in test file

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: salmonumbrella

internal/cmd/docs_write_update_test.go

@@ -303,8 +303,8 @@ func TestDocsWriteUpdate_FileInputErrors(t *testing.T) {
 	// Test with empty file
 	tmpDir := t.TempDir()
 	emptyFile := filepath.Join(tmpDir, "empty.txt")
-	if err := os.WriteFile(emptyFile, []byte(""), 0o600); err != nil {
-		t.Fatalf("write empty temp file: %v", err)
+	if writeErr := os.WriteFile(emptyFile, []byte(""), 0o600); writeErr != nil {
+		t.Fatalf("write empty temp file: %v", writeErr)
 	}
 	err = runKong(t, &DocsWriteCmd{}, []string{"doc1", "--file", emptyFile}, ctx, flags)
 	if err == nil {
@@ -316,8 +316,8 @@ func TestDocsWriteUpdate_FileInputErrors(t *testing.T) {
 
 	// Test that --text and --file are mutually exclusive
 	testFile := filepath.Join(tmpDir, "test.txt")
-	if err := os.WriteFile(testFile, []byte("content"), 0o600); err != nil {
-		t.Fatalf("write test temp file: %v", err)
+	if writeErr := os.WriteFile(testFile, []byte("content"), 0o600); writeErr != nil {
+		t.Fatalf("write test temp file: %v", writeErr)
 	}
 	err = runKong(t, &DocsWriteCmd{}, []string{"doc1", "--text", "hello", "--file", testFile}, ctx, flags)
 	if err == nil {

internal/cmd/root.go

@@ -21,6 +21,8 @@ import (
 const (
 	colorAuto  = "auto"
 	colorNever = "never"
+	boolTrue   = "true"
+	boolFalse  = "false"
 )
 
 type RootFlags struct {
@@ -163,9 +165,9 @@ func envOr(key, fallback string) string {
 
 func boolString(v bool) string {
 	if v {
-		return "true"
+		return boolTrue
 	}
-	return "false"
+	return boolFalse
 }
 
 func newParser(description string) (*kong.Kong, *CLI, error) {