refactor: remove unused ParseTLSVersion and app setter tests

- Remove sslutil.ParseTLSVersion (singular): unused, ParseTLSVersions (plural) is used
- Remove TestSetPidFile and TestSetLogFile: trivial setter tests

internal/app/app_test.go

@@ -110,30 +110,6 @@ func TestNewApp(t *testing.T) {
 	}
 }
 
-// TestSetPidFile 测试 SetPidFile setter 方法。
-func TestSetPidFile(t *testing.T) {
-	app := NewApp("/test/config.yaml")
-	pidPath := "/var/run/lolly.pid"
-
-	app.SetPidFile(pidPath)
-
-	if app.pidFile != pidPath {
-		t.Errorf("pidFile = %q, want %q", app.pidFile, pidPath)
-	}
-}
-
-// TestSetLogFile 测试 SetLogFile setter 方法。
-func TestSetLogFile(t *testing.T) {
-	app := NewApp("/test/config.yaml")
-	logPath := "/var/log/lolly.log"
-
-	app.SetLogFile(logPath)
-
-	if app.logFile != logPath {
-		t.Errorf("logFile = %q, want %q", app.logFile, logPath)
-	}
-}
-
 // TestSigName 测试信号名称辅助函数。
 func TestSigName(t *testing.T) {
 	tests := []struct {

internal/sslutil/tlsconfig.go

@@ -15,31 +15,6 @@ const (
 	tlsV13Upper = "TLSV1.3"
 )
 
-// ParseTLSVersion parses a TLS version string to a tls constant.
-//
-// Parameters:
-//   - version: TLS version string (e.g., "TLSv1.0", "TLSv1.1", "TLSv1.2", "TLSv1.3")
-//
-// Returns:
-//   - uint16: TLS version constant
-//   - error: Invalid version string returns error
-func ParseTLSVersion(version string) (uint16, error) {
-	switch version {
-	case "TLSv1.0", "TLSV1.0":
-		return tls.VersionTLS10, nil
-	case "TLSv1.1", "TLSV1.1":
-		return tls.VersionTLS11, nil
-	case tlsV12Lower, tlsV12Upper:
-		return tls.VersionTLS12, nil
-	case tlsV13Lower, tlsV13Upper:
-		return tls.VersionTLS13, nil
-	case "":
-		return 0, nil // Empty string means use default
-	default:
-		return 0, fmt.Errorf("invalid TLS version: %s", version)
-	}
-}
-
 // ParseTLSVersions parses TLS protocol version strings.
 //
 // Returns minimum and maximum TLS versions.