refactor: replace 'any' types with proper TypeScript interfaces

Major type safety improvements throughout the codebase:

- Updated DEFAULT_CONFIG version to 4.2
- Replaced 'any' with proper types in systemd.ts:
  * displaySingleUpsStatus now uses IUpsConfig and NupstSnmp types
  * Fixed legacy config handling to use proper IUpsConfig format
  * Removed inline 'any' type annotations

- Replaced 'any' with proper types in daemon.ts:
  * emergencyUps now properly typed as { ups: IUpsConfig, status: ISnmpUpsStatus }
  * Exported IUpsStatus interface for reuse
  * Added ISnmpUpsStatus import to disambiguate from daemon's IUpsStatus

- Replaced 'any' with Record<string, unknown> in migration system:
  * Updated BaseMigration abstract class signatures
  * Updated MigrationRunner.run() signature
  * Updated migration-v4.0-to-v4.1.ts to use proper types
  * Migrations use Record<string, unknown> because they deal with
    unknown config schemas that are being upgraded

Benefits:
- TypeScript now catches type errors at compile time
- Would have caught the ups.thresholds bug earlier
- Better IDE autocomplete and type checking
- More maintainable and self-documenting code

ts/daemon.ts

@@ -4,7 +4,7 @@ import * as path from 'node:path';
 import { exec, execFile } from 'node:child_process';
 import { promisify } from 'node:util';
 import { NupstSnmp } from './snmp/manager.ts';
-import type { ISnmpConfig } from './snmp/types.ts';
+import type { ISnmpConfig, IUpsStatus as ISnmpUpsStatus } from './snmp/types.ts';
 import { logger, type ITableColumn } from './logger.ts';
 import { MigrationRunner } from './migrations/index.ts';
 import { theme, symbols, getBatteryColor, getRuntimeColor, formatPowerStatus } from './colors.ts';
@@ -76,7 +76,7 @@ export interface INupstConfig {
 /**
  * UPS status tracking interface
  */
-interface IUpsStatus {
+export interface IUpsStatus {
   id: string;
   name: string;
   powerStatus: 'online' | 'onBattery' | 'unknown';
@@ -96,7 +96,7 @@ export class NupstDaemon {
 
   /** Default configuration */
   private readonly DEFAULT_CONFIG: INupstConfig = {
-    version: '4.1',
+    version: '4.2',
     upsDevices: [
       {
         id: 'default',
@@ -171,11 +171,13 @@ export class NupstDaemon {
       const { config: migratedConfig, migrated } = await migrationRunner.run(parsedConfig);
 
       // Save migrated config back to disk if any migrations ran
+      // Cast to INupstConfig since migrations ensure the output is valid
+      const validConfig = migratedConfig as unknown as INupstConfig;
       if (migrated) {
-        this.config = migratedConfig;
+        this.config = validConfig;
         await this.saveConfig(this.config);
       } else {
-        this.config = migratedConfig;
+        this.config = validConfig;
       }
 
       return this.config;
@@ -760,7 +762,7 @@ export class NupstDaemon {
 
         const rows: Array<Record<string, string>> = [];
         let emergencyDetected = false;
-        let emergencyUps: any = null;
+        let emergencyUps: { ups: IUpsConfig; status: ISnmpUpsStatus } | null = null;
 
         // Check all UPS devices
         for (const ups of this.config.upsDevices) {

ts/migrations/base-migration.ts

@@ -28,18 +28,18 @@ export abstract class BaseMigration {
   /**
    * Check if this migration should run on the given config
    *
-   * @param config - Raw configuration object to check
+   * @param config - Raw configuration object to check (unknown schema for migrations)
    * @returns True if migration should run, false otherwise
    */
-  abstract shouldRun(config: any): Promise<boolean>;
+  abstract shouldRun(config: Record<string, unknown>): Promise<boolean>;
 
   /**
    * Perform the migration on the given config
    *
-   * @param config - Raw configuration object to migrate
+   * @param config - Raw configuration object to migrate (unknown schema for migrations)
    * @returns Migrated configuration object
    */
-  abstract migrate(config: any): Promise<any>;
+  abstract migrate(config: Record<string, unknown>): Promise<Record<string, unknown>>;
 
   /**
    * Get human-readable name for this migration

ts/migrations/migration-runner.ts

@@ -32,7 +32,9 @@ export class MigrationRunner {
    * @param config - Raw configuration object to migrate
    * @returns Migrated configuration and whether migrations ran
    */
-  async run(config: any): Promise<{ config: any; migrated: boolean }> {
+  async run(
+    config: Record<string, unknown>,
+  ): Promise<{ config: Record<string, unknown>; migrated: boolean }> {
     let currentConfig = config;
     let anyMigrationsRan = false;
 

ts/migrations/migration-v4.0-to-v4.1.ts

@@ -49,15 +49,15 @@ export class MigrationV4_0ToV4_1 extends BaseMigration {
   readonly fromVersion = '4.0';
   readonly toVersion = '4.1';
 
-  async shouldRun(config: any): Promise<boolean> {
+  async shouldRun(config: Record<string, unknown>): Promise<boolean> {
     // Run if config is version 4.0
     if (config.version === '4.0') {
       return true;
     }
 
     // Also run if config has upsDevices with thresholds at UPS level (v4.0 format)
-    if (config.upsDevices && config.upsDevices.length > 0) {
+    if (Array.isArray(config.upsDevices) && config.upsDevices.length > 0) {
-      const firstDevice = config.upsDevices[0];
+      const firstDevice = config.upsDevices[0] as Record<string, unknown>;
       // v4.0 has thresholds at UPS level, v4.1 has them in actions
       return firstDevice.thresholds !== undefined;
     }
@@ -65,14 +65,15 @@ export class MigrationV4_0ToV4_1 extends BaseMigration {
     return false;
   }
 
-  async migrate(config: any): Promise<any> {
+  async migrate(config: Record<string, unknown>): Promise<Record<string, unknown>> {
     logger.info(`${this.getName()}: Migrating v4.0 config to v4.1 format...`);
     logger.dim(`  - Moving thresholds from UPS level to action level`);
     logger.dim(`  - Creating default shutdown actions from existing thresholds`);
 
     // Migrate UPS devices
-    const migratedDevices = (config.upsDevices || []).map((device: any) => {
+    const devices = (config.upsDevices as Array<Record<string, unknown>>) || [];
-      const migrated: any = {
+    const migratedDevices = devices.map((device) => {
+      const migrated: Record<string, unknown> = {
         id: device.id,
         name: device.name,
         snmp: device.snmp,
@@ -80,20 +81,21 @@ export class MigrationV4_0ToV4_1 extends BaseMigration {
       };
 
       // If device has thresholds at UPS level, convert to shutdown action
-      if (device.thresholds) {
+      const deviceThresholds = device.thresholds as { battery: number; runtime: number } | undefined;
+      if (deviceThresholds) {
         migrated.actions = [
           {
             type: 'shutdown',
             thresholds: {
-              battery: device.thresholds.battery,
+              battery: deviceThresholds.battery,
-              runtime: device.thresholds.runtime,
+              runtime: deviceThresholds.runtime,
             },
             triggerMode: 'onlyThresholds', // Preserve old behavior (only on threshold violation)
             shutdownDelay: 5, // Default delay
           },
         ];
         logger.dim(
-          `    → ${device.name}: Created shutdown action (battery: ${device.thresholds.battery}%, runtime: ${device.thresholds.runtime}min)`,
+          `    → ${device.name}: Created shutdown action (battery: ${deviceThresholds.battery}%, runtime: ${deviceThresholds.runtime}min)`,
         );
       } else {
         // No thresholds, just add empty actions array
@@ -104,7 +106,8 @@ export class MigrationV4_0ToV4_1 extends BaseMigration {
     });
 
     // Add actions to groups
-    const migratedGroups = (config.groups || []).map((group: any) => ({
+    const groups = (config.groups as Array<Record<string, unknown>>) || [];
+    const migratedGroups = groups.map((group) => ({
       ...group,
       actions: group.actions || [],
     }));

ts/systemd.ts

@@ -1,7 +1,8 @@
 import process from 'node:process';
 import { promises as fs } from 'node:fs';
 import { execSync } from 'node:child_process';
-import { NupstDaemon } from './daemon.ts';
+import { NupstDaemon, type IUpsConfig } from './daemon.ts';
+import { NupstSnmp } from './snmp/manager.ts';
 import { logger } from './logger.ts';
 import { theme, symbols, getBatteryColor, getRuntimeColor, formatPowerStatus } from './colors.ts';
 
@@ -277,14 +278,23 @@ WantedBy=multi-user.target
           await this.displaySingleUpsStatus(ups, snmp);
         }
       } else if (config.snmp) {
-        // Legacy single UPS configuration
+        // Legacy single UPS configuration (v1/v2 format)
         logger.info('UPS Devices (1):');
-        const legacyUps = {
+        const legacyUps: IUpsConfig = {
           id: 'default',
           name: 'Default UPS',
           snmp: config.snmp,
-          thresholds: config.thresholds,
           groups: [],
+          actions: config.thresholds
+            ? [
+                {
+                  type: 'shutdown',
+                  thresholds: config.thresholds,
+                  triggerMode: 'onlyThresholds',
+                  shutdownDelay: 5,
+                },
+              ]
+            : [],
         };
 
         await this.displaySingleUpsStatus(legacyUps, snmp);
@@ -307,7 +317,7 @@ WantedBy=multi-user.target
    * @param ups UPS configuration
    * @param snmp SNMP manager
    */
-  private async displaySingleUpsStatus(ups: any, snmp: any): Promise<void> {
+  private async displaySingleUpsStatus(ups: IUpsConfig, snmp: NupstSnmp): Promise<void> {
     try {
       // Create a test config with a short timeout
       const testConfig = {
@@ -332,7 +342,7 @@ WantedBy=multi-user.target
       const batteryColor = getBatteryColor(status.batteryCapacity);
 
       // Get threshold from actions (if any action has thresholds defined)
-      const actionWithThresholds = ups.actions?.find((action: any) => action.thresholds);
+      const actionWithThresholds = ups.actions?.find((action) => action.thresholds);
       const batteryThreshold = actionWithThresholds?.thresholds?.battery;
       const batterySymbol = batteryThreshold !== undefined && status.batteryCapacity >= batteryThreshold
         ? symbols.success