[DRAFT][v5-lts] Experimental macOS Apple Silicon bring-up for Valheim

[bbauti]

Summary

This branch contains my local bring-up work for running Valheim mods through BepInEx v5-lts on macOS Apple Silicon.

It currently includes:

• macOS runtime / launcher adjustments
• package reference updates needed for my Apple Silicon tests
• a submodule bump for BepInEx.Harmony
• minimal smoke-test plugins used during validation
• Valheim-specific helper scripts and notes I used to reproduce/install/test locally

Important note

This is probably too broad for a normal upstream PR and I am happy to split it if needed.
I also expect this PR to depend on the corresponding BepInEx.Harmony PR.

Validation

• native Valheim arm64 launched on a local Apple Silicon Mac
• BepInEx preloader and chainloader started successfully
• minimal no-Harmony and Harmony smoke tests loaded
• real Valheim mods loaded in my local setup
• I also used this branch while debugging a separate ServerCharacters startup issue on macOS

AI disclosure

This branch 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.

Dependency

Depends on: BepInEx/BepInEx.Harmony#4

[bbauti]

This PR is still blocked on the Harmony submodule dependency:
BepInEx/BepInEx.Harmony#4

Right now this branch points submodules/BepInEx.Harmony to my custom commit f16083f, so I do not expect this PR to be merged as-is yet.

My plan is:

1. wait for the Harmony PR to merge, or otherwise for an equivalent commit to exist in the public submodule remote
2. update this PR to point at that upstream-accessible submodule commit
3. only then ask for review here

No rush on this one.