App crashes when I try to search after the index is loaded.

- The main cause of the previous issue: #4
The main cause was that the index file, `images.uform3-image-text-english-small.usearch`, was missing both in the project and target membership.
After manually adding the index file, the app can read the `imageIndex` from the bundle file.

- However, the app crashes if I try to search after the index is fully loaded.
I wonder that USearchIndex.load() might need a fix.
This also happens when I load the index file saved by a previous PR: #7

Xcode: 16.1
MacOS: Sonoma 14.7.1
Device: iPhone 16 Plus - iOS 18.0
Simulator: iPhone 16 - iOS 18. 1, iPhone SE 3rd Gen - iOS 17.5

Console Log:
```
Wants to filter images by B
libc++abi: terminating due to uncaught exception of type std::runtime_error: No available threads to lock
Type: studio
```

Stack images:

Start by reading issues #4 and #7, then trace how USearchIndex.load() relates to the search triggered after the index finishes loading. Reproduce the crash on the reported Apple device or simulator and use the provided console log and stack images to investigate; done means searching after loading no longer crashes.

Written by the indexing model from the issue text.