Slow performance with lots of contacts

Since my app was being very slow on their computer (MBP 16" 2019), I got a friend to run this:

```js
const nmc = require('node-mac-contacts')
console.time('done')
const c = nmc.getAllContacts(['contactImage', 'contactThumbnailImage', 'jobTitle', 'departmentName', 'organizationName', 'middleName', 'note', 'socialProfiles'])
console.log(c.length, 'contacts')
console.timeEnd('done')
```

It took 16s for ~4k contacts.

> 3705 contacts
> done: 16798.31201171875ms

Thought it might be the image buffers so asked them to run:
```js
console.time('done')
console.log(require('node-mac-contacts').getAllContacts().length, 'contacts')
console.timeEnd('done')
```

It still took 12s.

Any ideas on how to make it faster or debug this? I created 4k contacts with a first and last name on my Mac but it didn't slow it up much:

> 4135 contacts
> done: 319.488037109375ms

I'll use a worker and cache the results as a workaround. I'm curious why it takes so long.

Start by reproducing the reported getAllContacts benchmarks on macOS with and without the listed contact fields, comparing the 16-second and 319-ms cases. Trace the node-mac-contacts implementation to identify why similar contact counts differ so greatly; done means the cause is understood and a measurable performance improvement or clear limitation is documented.

Written by the indexing model from the issue text.