Root certificate no longer applicable for leaf certificates in MacOS 26.1

## Environment

* MacOS 26.1
* mkcert version (from `mkcert -version`): 1.4.4
* Server (where the certificate is loaded): Nitro 2.12.9, Vite 7.1.12
* Client (e.g. browser, CLI tool, or script): All MacOS browsers

## What you did

Updated to MacOS 26.1
None of my local dev certificates work. They all worked before the update.

```
mkcert -uninstall
mkcert -install
```

Open keychain access and ensure mkcert root is Always Trusted

```
mkcert testsite.wip
yarn dev -o
```

This opens browser and normally would take me to https://testsite.wip (or whatever hostname I've set) without any SSL error.

## What went wrong

Since updating to MacOS 26.1 all my browsers report a certificate error - net::ERR_CERT_AUTHORITY_INVALID

"This server could not prove that it is testsite.wip; its security certificate is not trusted by your computer's operating system. This may be caused by a misconfiguration or an attacker intercepting your connection."

`openssl s_client -connect testsite.wip:3000 -servername testsite.wip -showcerts