This will fix a lot of weird problems that are based on file access
issues.

As discussed in
https://github.com/zed-industries/zed/pull/31219#issuecomment-2905371710,
for now it's better to just prevent running Zed with root privileges.

Release Notes:

- Explicitly disallow running Zed with root privileges

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Co-authored-by: Peter Tripp <peter@zed.dev>