feat(auth): add token time restriction validation

[ChrisPC-39]

🔗 Related Issue

Fixes part of #2393

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📝 Summary

When generating an API Token with time restrictions, the days list, start_time and end_time were not validated. This PR fixes the issue and adds unit tests.

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🏷️ Type of Change

• Bug fix
• Feature / Enhancement
• Documentation
• Refactor
• Chore (deps, CI, tooling)
• Other (describe below)

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🧪 Verification

Check	Command	Status
Lint suite	make lint	passed
Unit tests	make test	passed
Coverage ≥ 80%	make coverage	99%

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✅ Checklist

• Code formatted (make black isort pre-commit)
• Tests added/updated for changes
• Documentation updated (if applicable)
• No secrets or credentials committed

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[crivetimihai]

Thanks @ChrisPC-39. This is a nice addition — time-windowed token access is a useful RBAC feature. A few notes:

1. This is a new feature, not a bug fix — I've re-categorized accordingly.
2. The commit needs a Signed-off-by line (DCO requirement — use git commit --amend -s).
3. Please link the issue this addresses, or open one if there isn't one.
4. Consider whether pytz is the right choice — the stdlib zoneinfo module (Python 3.9+) is preferred for new code.

Let me know if you have questions!