Title: Add global HTTP exception filter tests

[Uyoxy]

Labels: testing good first issue

Description

src/common/filters/http-exception.filter.ts exists but has no unit
tests. Without tests, regressions in error response formatting go
undetected.

Implementation Requirements

• Add unit tests for src/common/filters/http-exception.filter.ts
• Cover: 400, 401, 403, 404, 500 responses
• Verify response format matches src/common/interfaces/error-response.interface.ts

Acceptance Criteria

• Tests cover all major HTTP error codes
• Response format matches error response interface
• All tests pass with npm test
• CI checks pass before PR is merged

Evidence Required

Contributors must provide ALL of the following:

• Screenshot of npm test passing with new tests
• Screenshot of passing CI checks on the PR

Files Affected

• src/common/filters/http-exception.filter.ts (modify)
• src/common/filters/http-exception.filter.spec.ts (create)

[SharifIbrahimDev]

Hi, I'd like to work on this issue.

I have experience writing unit tests for NestJS applications and validating API error handling. I can add comprehensive tests for the global HTTP exception filter, covering 400, 401, 403, 404, and 500 responses while ensuring the response structure conforms to error-response.interface.ts.

I will create a robust test suite in http-exception.filter.spec.ts, verify that all tests pass with npm test, and ensure CI checks pass before submitting the PR. I will also provide the required screenshots of successful test execution and CI status.

My goal is to deliver a maintainable test suite that prevents regressions and improves confidence in the API's error response behavior.