pnpm upgrade Nothing to stop. No server is running for the store

pnpm add -g pnpm
Nothing to stop. No server is running for the store at /Users/pan/Library/pnpm/store/v3
 ERR_PNPM_REGISTRIES_MISMATCH  This modules directory was created using the following registries configuration: {"default":"https://registry.npmmirror.com/"}. The current configuration is {"default":"https://registry.npmjs.org/"}. To recreate the modules directory using the new settings, run "pnpm install".

It seems like you're trying to globally install pnpm using pnpm add -g pnpm, but you're encountering an error because the registry used to create your current modules directory is different from the registry you're currently using.

Here's what you can do to solve the issue:

Change your registry back to the one used to create the modules directory. You can do that by running:
```
npm config set registry https://registry.npmmirror.com/
```
After running the above command, you can try running pnpm add -g pnpm again. If it works, then you're done.
If you want to continue using https://registry.npmjs.org/ as your registry, you'll need to recreate the modules directory using the new registry settings. You can do that by running:
```
pnpm install
```
This command will recreate your modules directory. Once done, try running pnpm add -g pnpm again.
If you're still encountering issues, you might want to clear the cache. You can do this by running:
```
pnpm cache clean
```
Then try installing pnpm again.

Please note that you need to replace npm with pnpm in the commands if you have pnpm installed and are using it instead of npm. If pnpm is not working, you might need to install pnpm with npm first:

npm install -g pnpm