Implemented sounds routing with CRUD, voting, and file upload endpoints

[Wikijito7]

Solves #6

📋 Changelist Summary

Implemented full sounds routing: data model updates, repository logic, audio file storage, MongoDB data source, and 9 API endpoints.

💬 Description

This PR completes the sounds feature that was partially stubbed out. It includes:

• Data model: Added SoundUserBO/DBO/DTO (simplified user for votes), description and status fields to sounds, VoteRequestDTO and UpdateSoundRequestDTO
• Data source: Created SoundsLocalDataSource with MongoDB collection registration and paginated queries
• File storage: Created SoundFileService for saving, serving, and deleting audio files (non-deprecated Ktor API)
• Repository: Full implementation of SoundRepositoryImpl with all CRUD operations, voting logic, and file management
• Routes: 9 endpoints under authenticate {}:
  • GET /sounds — list with pagination
  • GET /sound/{id} — sound detail
  • GET /sound/{id}/file — serve audio
  • POST /sound — create (multipart with title + audio)
  • PUT /sound/{id} — update metadata
  • DELETE /sound/{id} — delete sound
  • POST /sound/{id}/vote — vote up/down
  • POST /sound/{id}/file — replace audio
  • GET /user/sounds — user's own sounds

This PR was generated using AI assistance. Please review carefully.

[Wikijito7]

3 issues found during frontend review. The soundUrl (🔴) is a blocker — fixing it in the mapper is the simplest approach.

[sonarqubecloud]

Quality Gate failed

Failed conditions
9.3% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud