♻️ Run doc-test generation as an explicit CI step

Drop the `pretest:ci` lifecycle hook and call `create:doc-tests` from the
`build` job before `test:ci`. The hook hid the step from the job log and
made `test:ci` behave differently under npm than when run directly.

src/doc-test/README.md

@@ -7,6 +7,6 @@ formats them with `oxfmt`, then type-checks them with
 [`tsconfig.json`](./tsconfig.json) — the scoped config that relaxes
 `noUnusedLocals` so example-only locals (and the injected `assert`) compile.
 
-CI regenerates them first via `pretest:ci`; the fast local `test` / `verify`
-tiers do not. See [development/docs.md](../../development/docs.md) for why the
+CI regenerates them in an explicit step before `test:ci`; the fast local `test` /
+`verify` tiers do not. See [development/docs.md](../../development/docs.md) for why the
 generator is shaped this way.