feat(backend): add placeholder error tracking integration

[code-0-stella]

feat(backend): add placeholder error tracking integration

Body:

Summary

• add a placeholder error tracking service under the backend logging path
• capture exception and rejection events in a structured report
• register the logging module with the Nest app
• add unit tests covering report creation and initialization

Testing

• npm test -- --runInBand --runTestsByPath src/logging/error-tracking.service.spec.ts

Closes: #215

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[MaryammAli]

LGTM