Suggestion: Noise functions for @std/random

Add the following noise functions to `@std/random` with function signatures like:

```typescript
function perlin(x: number, y?: number, z?: number): number

function simplex(x: number, y?: number, z?: number, w?: number): number
```

I’ve been looking for a stable implementation of noise functions for some graphical use cases. It would be great if they supported seeding. There are more noise algorithms that are also useful for complex graphics but these two would be a good starting point.

The issue names the @std/random package entry point but no files or tests. Start by locating that package and reviewing how the proposed perlin and simplex signatures, optional dimensions, and seeding requirement should fit its API. Done means both functions are available with the requested signatures and stable seeded behavior.

Written by the indexing model from the issue text.