tsconfig.strict.json is the build config with strictNullChecks and
noImplicitAny on. lint:strict runs tsc over it and holds the errors per file
to scripts/strict-baseline.json (204 in 109 files today): a file may only
lose errors, a new file starts at none, and an entry above its count fails
until --update lowers it. An error outside any file or an unreadable tsc run
fails closed. It runs in the server job; the build itself stays on
strict: false.
Maurice