chore: raise the pnpm pin to ^12.4.1 (#89)

Raises the pnpm pin in `devEngines.packageManager` from `^12.0.0` to
`^12.4.1` and records 12.4.1 in `pnpm-lock.yaml` (previously 12.3.4),
the same change as middleapi/orpc#2012. With a range pin, any
environment that launches pnpm through Corepack resolves the range to
the newest 12.x on npm and cannot switch to the version recorded in the
lockfile, so an older lockfile pin fails `pnpm install
--frozen-lockfile` with
`ERR_PNPM_FROZEN_LOCKFILE_WITH_OUTDATED_LOCKFILE`. Keeping the pin at
the current release avoids that.

## Behavior

- The lockfile diff is limited to the `packageManagerDependencies` block
and the `@pnpm/exe.*` platform packages for 12.4.1.
- The next pnpm 12.x release needs another refresh (`pnpm self-update
<version>` followed by `pnpm install`).

## Testing

- `pnpm install --frozen-lockfile` passes with pnpm 12.4.1: the
supply-chain check passes and the resolution step is skipped.
- `eslint package.json` passes.

Author: dinwwwh

package.json

@@ -7,7 +7,7 @@
   "devEngines": {
     "packageManager": {
       "name": "pnpm",
-      "version": "^12.0.0",
+      "version": "^12.4.1",
       "onFail": "download"
     }
   },