#[server_function]Expand description
Defines a bounded, dual-target Rullst server function.
The annotated item must be a concrete async free function with at most 16
identifier parameters and a rullst::rpc::RpcResult<T> return type. Native
builds retain its body and generate <name>_rpc_router(). Wasm builds
serialize the arguments into the versioned rullst.client envelope and call
the exact generated endpoint.
path = "/api/rpc/..." is optional; otherwise the final path segment is the
function name. Mount the generated router before applying Rullst’s
production security and application identity/authorization layers.