refactor: remove unused tests, mocks, and outdated e2e configurations

Deleted unused e2e tests, mocks (`cuid2`, `jose`, `ml-kem`, `sha3`), and their associated jest configurations. Simplified services by ensuring proper dependency imports, resolving circular references, and improving TypeScript type usage for enhanced maintainability and testability. Upgraded Dockerfile base image to match new development standards.

backend/src/media/strategies/media-processor.strategy.ts

@@ -2,5 +2,8 @@ import type { MediaProcessingResult } from "../../common/interfaces/media.interf
 
 export interface IMediaProcessorStrategy {
 	canHandle(mimeType: string): boolean;
-	process(buffer: Buffer, options?: any): Promise<MediaProcessingResult>;
+	process(
+		buffer: Buffer,
+		options?: Record<string, unknown>,
+	): Promise<MediaProcessingResult>;
 }