Follow-up to #39758, this PR makes sure that CSS imports (both global and CSS modules) from client components are not handled by mini-css-extract's HMR logic. Instead, we trigger a server component update and let the client to refetch the RSC payload.
However, we are still leveraging the mini-css-extract plugin to emit CSS assets. So in this PR we add a new pitch loader to calculate the original file hash, but replace the final content to eliminate HMR logic but only keep the hash (so hot reloader can keep tracking that).
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
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