feat(snmp): add configurable SNMP runtime units with v4.3 migration support

ts/daemon.ts

@@ -142,7 +142,7 @@ export class NupstDaemon {
 
   /** Default configuration */
   private readonly DEFAULT_CONFIG: INupstConfig = {
-    version: '4.2',
+    version: '4.3',
     upsDevices: [
       {
         id: 'default',
@@ -162,6 +162,7 @@ export class NupstDaemon {
           privKey: '',
           // UPS model for OID selection
           upsModel: 'cyberpower',
+          runtimeUnit: 'ticks',
         },
         groups: [],
         actions: [
@@ -260,7 +261,7 @@ export class NupstDaemon {
 
       // Ensure version is always set and remove legacy fields before saving
       const configToSave: INupstConfig = {
-        version: '4.2',
+        version: '4.3',
         upsDevices: config.upsDevices,
         groups: config.groups,
         checkInterval: config.checkInterval,