Add prepared build artifacts, browser host and the build and
purge commands for the CLJS renderer benchmarks.
Each preparation attempt gets a build ID and a retained directory with
its manifest, log, Node case catalog, browser bundle, renderer files
and host page. Ready builds load their matching catalog in process and
serve only their own directory through an owned loopback host.
Own Chromium through a bounded process group, verify the compiled build
identity before execution and retain failed preparations for diagnosis.
Wire the diagnostic pilot to the same build, catalog, server and
browser APIs.
Add real boundary tests for artifacts, processes, servers, browsers and
CLI parsing, and register them with the performance test runner. Rename
the benchmark lint and test scripts to match the suite.
AI-assisted-by: deepseek-flash
