fix: resolve pagination termination logic and empty page fallback

[Saadat555]

Resolves #1

This PR fixes the pagination issues identified in Issue #1 by ensuring that the pagination loop terminates correctly:

1. It parses the Link header accurately using regex to find the rel="next" page URL.
2. It explicitly checks for empty API responses (len(issues) == 0) and safely aborts to prevent infinite loop regressions, as requested in the acceptance criteria.
3. It enforces the requested total limit natively.
4. Unit tests have been adjusted/added to properly simulate sparse/partial pages and the empty-page circuit breaker.

/claim #1

[opirebot]

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