HyperCasual utils

```ts
const isFunction = (fn: any): boolean => typeof fn === 'function'
```

```ts
const groupBy = (xs: any[], key: string) => {
return xs.reduce((rv, x) => {
(rv[x[key]] = rv[x[key]] || []).push(x)
return rv
}, {})
}
```

```ts
const shortAddress = (address: string): string => {
if (address) {
return `${address.slice(0, 6)}...${address.slice(-6)}`
}
return ''
}
```

Start by searching the TypeScript packages monorepo for the appropriate utility module and any existing exports or tests. Confirm where shared helpers belong, then add the requested utilities and verify that the relevant package exposes them and its checks pass.

Written by the indexing model from the issue text.