buildKSlides
Evaluates the kslides DSL and validates the result without emitting any output: no files are written and no HTTP server is started, but all configuration blocks (including output {}) are applied. Used by tooling that renders presentations on its own terms — e.g. exportPdf() in the kslides-export module, which serves the built KSlides from an ephemeral-port server via KSlides.startHttpServer.
Return
the populated KSlides instance.
Parameters
block
the same configuration block accepted by kslides.
Throws
if no KSlides.presentation blocks are declared, or if any presentation contains zero slides.