🎨 Narrow AbortAddon controller() return type to AbortController

[Ruby-Leung]

What

.controller() is typed as () => [any, this], so the first element of the returned pair is any. At runtime it is always the request's AbortController (created in beforeRequest), so this narrows the type to [AbortController, this].

Why

With any, callers lose all type safety on the returned controller — the documented c.abort() usage isn't checked, and typos slip through silently:

const [c, w] = wretch(url).addon(AbortAddon()).get().controller()
c.abort()   // now type-checked
c.signl     // now a compile error instead of silently `any`

This is a type-only change — runtime behaviour is unchanged. (Same spirit as #314.)

Tests

Adds test/types/abort-controller.ts, which asserts the narrowed return type and includes a @ts-expect-error that fails if the type ever regresses back to any. npm run test:types and npm run test:node both pass locally.

[coveralls]

coverage: 97.839%. remained the same — Ruby-Leung:narrow-abort-controller-type into elbywan:master

[elbywan]

Looking good, thanks! 🙇