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/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