I’ve started to get more and more paranoid about this. It’s tough when you’re running untrusted code, but I think I’ve improved this by:

not storing SSH keys on the filesystem, and instead using an agent (like 1Password) to mediate access

Stop storing dev secrets/credentials on the filesystem, injecting them into processes with env vars or other mechanisms. Your password manager could have a way to do this.

Develop in a VM separate from your regular computer usage. On windows this is essential anyway through using WSL, but similar things exist for other OSs