docs: add general agent guidance

[EffortlessSteven]

Hey @LebedevRI, I’m working on a patch for issue #232 and saw y’all were working on AGENTS.md. If you’re interested, here are some tweaks to further encode the repo style into it.

Based on Codex’s codebase and style research, this adds:

• following nearby code style and keeping diffs small;
• treating decoder changes as correctness-sensitive;
• tracking raw samples by parsed metadata and SHA256, not filenames;
• avoiding rendered previews/thumbnails as decoder proof;
• keeping shared decoder state safe under OpenMP;
• using sample hashes/raw-plane evidence for validation;
• keeping commits narrow and reviewable.

Best,
Steven

[LebedevRI]

If nuclear weapons are banned, why would i extensively publicly document how to make them?

[EffortlessSteven]

Apologies, my mistake. I thought the intent was full disclosure of LLM use and more repo-aligned code from developers who use LLM-based tools.