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/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;