Time Attack and Speed Run Contract Implementation (#20)

[rainwaters11]

🎯 Time Attack and Speed Run Contract Implementation

Closes #20

📋 Summary

Implements a production-ready time attack mode contract for tracking fastest puzzle completion times with automatic leaderboard management, anti-cheat measures, and comprehensive testing.

✅ Completed Tasks

• Design time tracking data structure
• Implement time-stamped submission function
• Create global best time tracking
• Add daily/weekly leaderboard resets
• Implement time verification and anti-cheat
• Write timing accuracy tests (8 tests, all passing)
• Optimize timestamp storage

🎯 Acceptance Criteria

• ✅ Times recorded accurately
• ✅ Leaderboards update correctly
• ✅ Daily/weekly resets work
• ✅ Anti-cheat prevents manipulation
• ✅ Contract passes all tests and clippy checks

🧪 Testing

running 8 tests
test result:  ok. 8 passed; 0 failed; 0 ignored; 0 measured

📊 Code Quality

• ✅ 8/8 tests passing
• ✅ 0 clippy warnings
• ✅ Clean, documented code
• ✅ TTL-managed persistent storage

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Ready for review! 🚀

[rainwaters11]

✅ Merge conflict resolved - kept all workspace members (guild, staking, time_attack).

All tests still passing:

• 8/8 tests pass
• 0 clippy warnings
• Ready for review! 🚀