Server-Only Module Enforcer for React

The `server-only` package is a fundamental marker utility in the React Server Components (RSC) architecture. Its primary purpose is to enforce that a JavaScript module, and any code within it, can only be executed within a server-side environment. This is crucial for preventing sensitive server-side logic, such as database queries, direct file system access, or API keys, from accidentally being bundled and exposed to the client-side. The package achieves this through a clever use of conditional exports in its `package.json`. In a React Server Component build environment, it resolves to an empty file, effectively doing nothing. However, if imported into a client-side component, it resolves to a file that throws a build-time error, acting as a safeguard against data leaks, increased bundle sizes, and runtime failures. It is maintained by the React team, currently at version `0.0.1`, and its stability reflects its minimalistic and declarative role within the RSC paradigm. It differentiates itself by providing a strict, compile-time guarantee for server-only code separation, complementing newer runtime APIs like `experimental_taintObjectReference` which offer finer-grained control.