test : add unit tests for goal-tracker.ts

[tmdeveloper007]

Summary of What Needs to be Done:
Add unit tests for the goal-tracker.ts utility module covering submitGoalWithRefresh function.

Changes that Need to be Made:

• Create test/goal-tracker.test.ts
• Add tests for successful goal creation with commits/prs unit (calls handleSync)
• Add tests for successful goal creation with other units (calls loadGoals)
• Add tests for fetch failure (returns created=false with generic error)
• Add tests for non-ok response with custom error message from JSON
• Add tests for non-ok response without custom error (falls back to generic message)
• Add tests for handleSync throwing (returns created=true with partial error)
• Add tests for loadGoals throwing (returns created=true with partial error)
• Add tests for POST payload construction

Impact that it would Provide:
Increases test coverage and ensures goal submission handles all error cases gracefully.

Hello @Priyanshu-byte-coder, please assign this issue to me (@tmdeveloper007) so I can open a focused PR.