Add unit tests for event tracking provider

[phertyameen]

Description

Write unit tests for backend/src/analytics/providers/track-event.provider.ts covering the happy path, an empty-data edge case, and a boundary date-range case, using mocked repositories.

Why this matters

The event tracking provider currently lacks dedicated test coverage, so a regression could ship undetected.

Files to touch

• backend/src/analytics/providers/track-event.provider.spec.ts

Acceptance Criteria

• At least 3 test cases: happy path, empty data, boundary dates
• Repositories are mocked (no real DB connection in unit tests)
• Tests run under npm test with no manual setup

Notes

This issue is part of the new analytics module effort (tracking, aggregation,
and reporting on player/game activity). Please keep new code inside
backend/src/analytics/ following the same module/controller/service/provider
layout used by existing modules (e.g. progress, streak, quests).

[kiel997]

Hi! I'd like to work on this issue. I have experience writing unit tests for backend services using Jest and TypeScript, with a focus on mocking dependencies and verifying expected behaviour. I'll add comprehensive unit tests for the event tracking provider, cover both successful and error scenarios, and ensure the implementation maintains or improves the project's test coverage while following the existing testing conventions. I look forward to contributing this enhancement.

[grantfox-oss]

🦊 GrantFox — @kiel997 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #562)
2. Your PR will be reviewed by the MindBlockLabs maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@kiel997's PR #608 was approved and merged by @phertyameen.

🏆 @kiel997: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (239 total points). Track your full progress on GrantFox.

👏 Great work, @kiel997! Keep contributing to MindBlockLabs.