* Build: line tables only in dev, no debug info for dependencies
* Tests: one integration-test binary per crate
Each crate's tests/*.rs becomes a module of tests/it/main.rs. Files that
install process-wide state (the file io hooks, user aliases, SAVETIME and
SAVEFILEPATH, user linetype and pattern files, registered fonts) stay their
own test binaries.
* xtask ci: nextest, tests without examples, one wasm check call
