Remove all test files and related test dependencies

[terragon-labs]

Summary

• Completely removes the test suite from the repository
• Deletes all test files under src/croniter/tests/
• Removes test dependencies from requirements/test.txt and requirements/tox.txt
• Cleans up setup.cfg by removing coverage configuration
• Updates tox.ini to only run linting environment

Changes

Test Files

• Deleted all test files including:
  • test_croniter.py
  • test_croniter_dst_repetition.py
  • test_croniter_hash.py
  • test_croniter_random.py
  • test_croniter_range.py
  • test_croniter_speed.py

Dependencies

• Removed requirements/test.txt which contained pytest, coverage, mock, flake8, setuptools
• Removed tox-current-env from requirements/tox.txt
• Updated tox.ini to only run lint environment, removing test and coverage environments

Configuration

• Removed coverage run and report sections from setup.cfg

Rationale

• This PR removes all testing infrastructure and test code, possibly to prepare for a different testing strategy or to clean up the repository.

Test plan

• No tests remain in the repository after this change
• Linting environment remains active and can be run via tox
• Manual verification that no test files or test dependencies remain

🌿 Generated by Terry

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📎 Task: https://www.terragonlabs.com/task/ed8d2c2e-cfd4-4753-80bf-a810d4ddfc6b