Add LeetCode solution 00874

[eselyavka]

Summary

• replace the existing 00874 implementation with a simpler direction-index simulation
• track obstacles in a set for O(1) collision checks while moving step by step
• extend the inline unittest coverage with both LeetCode examples and a no-movement edge case

Testing

• ~/.venv/py3_11/bin/python -m pytest -q practice/leetcode/solutions_00600/solution_00874.py
• pre-commit hook during git commit ran the full repo test suite: 802 passed
• pre-commit hook during git commit ran pylint on the changed Python file: 10.00/10

Notes

• the previous version could return -inf when the command list never moved the robot; the updated implementation returns 0 for that case