internal/api stays a translation layer: decode (with
DisallowUnknownFields so typos 400 instead of silently defaulting),
run the engine, encode; all validation stays in the engine. Routes use
Go 1.22 mux patterns ('POST /api/comparison'), so wrong methods get
405 from the stdlib for free. httptest runs handlers fully in memory;
the API test re-pins the 99/70/7 golden values end to end.
ComparisonResponse is added to tygo.yaml with a type mapping so the
generated web/src/types/api.ts reuses the engine's TS types.
cmd/spreadlab now serves on -addr (default localhost:8080); -table
keeps the CLI comparison as a sanity check.
tygo is pinned via go.mod's tool directive (Go 1.24+): the tool's
version is locked like any dependency and runs as 'go tool tygo', no
global install. 'go generate ./...' regenerates web/src/types/engine.ts
from Config/Result and their json tags; the generated file is committed
so the frontend builds without Go installed. The go:generate directive
anchors in a root generate.go because generate runs commands from the
declaring file's directory and tygo reads tygo.yaml from the cwd.
go.mod's ignore directive (Go 1.25+) keeps ./... from crawling into
web/node_modules, where some npm packages ship stray .go files.
