[system-a] toys/ should also export dot

TODO.md

@@ -1,6 +1,5 @@
 # system-a
 
-[system-a] `toys/` should not have index.js
 [system-a] `Representation` -- `{ inflate, deflate, update }`
 
 - with `velocityAccumulationFactor`

src/system-a/targets/plane.ts

@@ -1,6 +1,5 @@
 import { type Tensor } from "../tensor/index.js"
-import { dot } from "../toys/dot.js"
-import { add } from "../toys/index.js"
+import { add, dot } from "../toys/index.js"
 
 export function plane(t: Tensor): (...ps: [Tensor, Tensor]) => Tensor {
   return (ps0, ps1) => add(dot(ps0, t), ps1)

src/system-a/toys/index.ts

@@ -1,2 +1,3 @@
+export * from "./dot.js"
 export * from "./sum.js"
 export * from "./toys.js"