Uint8Arrays are generic in recent TypeScript versions

`Uint8Array` is really `Uint8Array` and `ArrayBufferLike` can be `ArrayBuffer`, `SharedArrayBuffer`, and others.

In recent TypeScript versions this breaks on APIs that only accept `ArrayBuffer`s since `ArrayBufferLike` could be a `SharedArrayBuffer`.

`const foo = new Uint8Array()` makes `foo` be `Uint8Array` (great!), but the return type of `function foo (): Uint8Array { ... }` is interpreted as `Uint8Array` so might be a `SharedArrayBuffer` which breaks APIs like `new Blob([arr])` in TypeScript 5.9.x. Ugh.

It seems we need to change `function foo (): Uint8Array { ... }` to `function foo (): Uint8Array { ... }` everywhere and in all supporting modules. Double ugh.