`npm run typecheck` never typechecks `middleware/test/`

[Weegy]

middleware/tsconfig.json has include: ["src/**/*.ts"], so the test/ tree is outside the
project and npm run typecheck never sees it. A type error in a test file passes every gate and only
surfaces when tsx hits it at runtime — or does not surface at all, for a branch the test never
takes.

Noticed during PR #550, where an edited test file had to be typechecked by hand with the repo's own
compiler options to get any coverage at all.

Worth deciding deliberately rather than by omission: either add test/**/*.ts to the project, or add
a second tsconfig.test.json and a typecheck:test script wired into CI. The first is simpler; the
second avoids test types leaking into the shipped build's project graph.

Filed as a follow-up from PR #550 (MCP 2026-07-28 cluster, wave 4-6).