Per review: the method/version vocabulary is now closed TYPE unions
(@ts-check + jsdoc typedefs - InstallerVersion, InstallMethod,
UpdateMethod - checked with tsc --checkJs, which rejects a SPEC entry
outside the unions; verified by corrupting a copy: 6 errors) instead
of runtime KNOWN_METHODS/ALLOWED_VERSIONS sets. validateEntry and
routeWants are deleted with all the paranoia: the generator always
emits every OS matrix and the dispatch route filter moved to plain
job-level ifs in install-e2e.yml, where the OS jobs already live.
secondUpdate is typed never[] so declaring one is a type error until
a leg implements it. Anything types cannot catch is self-evident on
the next CI run.
17dea59026