build:artifacts produces every artifact, including the tsdown bundles,
the Desktop bundle, and Web, so naming it after sources undersold it;
build:check checks scripts, benchmarks, and website code besides tests.
The build.ts scopes, aggregate step ids, the Python builder flag
(--build-artifacts), workflows, callers, docs, and the build-split Agent
Note follow the new names. The note also records the naming
alternatives.
Refs #5852
imccyu
f6b0c5af59