Add HarmonyX 2.16 compatibility fixes for macOS arm64

[bbauti]

Summary

• update the interop layer for HarmonyX 2.16
• adjust reflection/attribute handling needed by my macOS arm64 Valheim bring-up
• this is the dependency I needed before testing the parent BepInEx v5-lts branch on Apple Silicon

Validation

• validated indirectly through a local BepInEx v5-lts Apple Silicon bring-up
• a minimal Harmony smoke test loaded successfully
• real Valheim mods using Harmony also loaded in my local setup

AI disclosure

This patch was generated with AI assistance from Codex based on GPT-5 and then validated locally by me. I am primarily a frontend web developer and I am not deeply comfortable in this language/codebase yet, so I completely understand if you do not want to review or merge AI-assisted changes. If this is not useful, please feel free to close it.