fix(types): augment ref unwrap bail types in appropriate packages

Packages can now augment the ref unwrap bail types in their own `d.ts`.
Also updated the build script to auto concat any files in a package's
`types` directory to the final generated `d.ts`.

- `@vue/reactivity` should no longer require `libs: ["DOM"]` in tsconfig
- Properly bail on `VNode` and `ComponentPublicInstance` in runtime-core

packages/reactivity/src/index.ts

@@ -9,7 +9,8 @@ export {
   triggerRef,
   Ref,
   UnwrapRef,
-  ToRefs
+  ToRefs,
+  RefUnwrapBailTypes
 } from './ref'
 export {
   reactive,