fix(lint): remove unnecessary async keywords from synchronous functions

- Remove async from functions that don't use await
- Change return types from Promise<void> to void for synchronous functions
- Fixes all 8 require-await lint warnings
- Reduces total lint warnings from 63 to 55

ts/cli/ups-handler.ts

@@ -977,7 +977,7 @@ export class UpsHandler {
    * Check if the systemd service is running and restart it if it is
    * This is useful after configuration changes
    */
-  public async restartServiceIfRunning(): Promise<void> {
+  public restartServiceIfRunning(): void {
     try {
       // Check if the service is active
       const isActive =

ts/daemon.ts

@@ -196,7 +196,7 @@ export class NupstDaemon {
   /**
    * Save configuration to file
    */
-  public async saveConfig(config: INupstConfig): Promise<void> {
+  public saveConfig(config: INupstConfig): void {
     try {
       const configDir = path.dirname(this.CONFIG_PATH);
       if (!fs.existsSync(configDir)) {

ts/nupst.ts

@@ -130,7 +130,7 @@ export class Nupst {
    * Get the latest version from npm registry
    * @returns Promise resolving to the latest version string
    */
-  private async getLatestVersion(): Promise<string> {
+  private getLatestVersion(): Promise<string> {
     return new Promise<string>((resolve, reject) => {
       const options = {
         hostname: 'registry.npmjs.org',

ts/snmp/manager.ts

@@ -88,7 +88,7 @@ export class NupstSnmp {
    * @param retryCount Current retry count (unused in this implementation)
    * @returns Promise resolving to the SNMP response value
    */
-  public async snmpGet(
+  public snmpGet(
     oid: string,
     config = this.DEFAULT_CONFIG,
     retryCount = 0,

ts/systemd.ts

@@ -119,7 +119,7 @@ WantedBy=multi-user.target
    * Stop the systemd service
    * @throws Error if stop fails
    */
-  public async stop(): Promise<void> {
+  public stop(): void {
     try {
       execSync('systemctl stop nupst.service');
       logger.success('NUPST service stopped');
@@ -168,7 +168,7 @@ WantedBy=multi-user.target
    * Display the systemd service status
    * @private
    */
-  private async displayServiceStatus(): Promise<void> {
+  private displayServiceStatus(): void {
     try {
       const serviceStatus = execSync('systemctl status nupst.service').toString();
       const boxWidth = 45;
@@ -315,7 +315,7 @@ WantedBy=multi-user.target
    * Stop the service if it's running
    * @private
    */
-  private async stopService(): Promise<void> {
+  private stopService(): void {
     try {
       logger.log('Stopping NUPST service...');
       execSync('systemctl stop nupst.service');
@@ -329,7 +329,7 @@ WantedBy=multi-user.target
    * Disable the service
    * @private
    */
-  private async disableService(): Promise<void> {
+  private disableService(): void {
     try {
       logger.log('Disabling NUPST service...');
       execSync('systemctl disable nupst.service');