Clean up D2EventTimerQueueStrc and Event.cpp readability

[AudriusButkevicius]

Summary

• Restructures D2EventTimerQueueStrc to use named members instead of opaque unk0x fields:
  • unk0x04[10][64] → pHead[5][64] + pTail[5][64]
  • unk0xA04[5] → pInfinite[5]
  • unk0xA18 → pCurrent
• Simplifies complex pointer arithmetic (bitshifts, manual offset calculations) into clean 2D array indexing
• Renames decompiler variable v19 → ppQueue

Fixes #191

Note: This PR was produced using Claude Code based on the upstream issue description. The change has not been compiled or tested, as the project requires a Windows build environment which was not available. Please review carefully before merging.