fix: resolve gosec integer overflow and unconvert issues

- Fix G115 integer overflow by converting uint32 to int comparison
- Remove unnecessary int() conversions for syscall constants
- syscall.Stdin/Stderr/Stdout are already int type

internal/secret/crypto.go

@@ -83,19 +83,19 @@ func DecryptWithPassphrase(encryptedData []byte, passphrase string) ([]byte, err
 // This version is for unlocking and doesn't require confirmation
 func ReadPassphrase(prompt string) (string, error) {
 	// Check if stdin is a terminal
-	if !term.IsTerminal(int(syscall.Stdin)) {
+	if !term.IsTerminal(syscall.Stdin) {
 		// Not a terminal - never read passphrases from piped input for security reasons
 		return "", fmt.Errorf("cannot read passphrase from non-terminal stdin (piped input or script). Please set the SB_UNLOCK_PASSPHRASE environment variable or run interactively")
 	}
 
 	// stdin is a terminal, check if stderr is also a terminal for interactive prompting
-	if !term.IsTerminal(int(syscall.Stderr)) {
+	if !term.IsTerminal(syscall.Stderr) {
 		return "", fmt.Errorf("cannot prompt for passphrase: stderr is not a terminal (running in non-interactive mode). Please set the SB_UNLOCK_PASSPHRASE environment variable")
 	}
 
 	// Both stdin and stderr are terminals - use secure password reading
 	fmt.Fprint(os.Stderr, prompt) // Write prompt to stderr, not stdout
-	passphrase, err := term.ReadPassword(int(syscall.Stdin))
+	passphrase, err := term.ReadPassword(syscall.Stdin)
 	if err != nil {
 		return "", fmt.Errorf("failed to read passphrase: %w", err)
 	}

internal/secret/debug.go

@@ -36,7 +36,7 @@ func InitDebugLogging() {
 	_, _, _ = syscall.Syscall(syscall.SYS_FCNTL, os.Stderr.Fd(), syscall.F_SETFL, syscall.O_SYNC)
 
 	// Check if STDERR is a TTY
-	isTTY := term.IsTerminal(int(syscall.Stderr))
+	isTTY := term.IsTerminal(syscall.Stderr)
 
 	var handler slog.Handler
 	if isTTY {

internal/secret/debug_test.go

@@ -64,7 +64,7 @@ func TestDebugLogging(t *testing.T) {
 
 				// Override the debug logger for testing
 				oldLogger := debugLogger
-				if term.IsTerminal(int(syscall.Stderr)) {
+				if term.IsTerminal(syscall.Stderr) {
 					// TTY: use colorized handler with our buffer
 					debugLogger = slog.New(newColorizedHandler(&buf))
 				} else {