Operation request: Proper Noun Case

## Summary

There should be a recipe for "proper noun" casing to convert proper nouns that aren't correctly first-letter capitalized.

Call it something like "proper noun case", or "first letter case"

Use case: convert text where there is a list of names or other proper nouns that are in all caps

The Get All Casings recipe is the closest to this, but there are a few issues https://github.com/gchq/CyberChef/pull/1328#issuecomment-2950721667, and it doesn't directly give just the proper noun case.

### Example Input
```
bob
bob jenkins
bob Jenkins
bob, alice, jim
BOB DEWITT, ALICE LIGHT, JIM SIMONS
```

### Example Output

```
Bob
Bob Jenkins
Bob Jenkins
Bob, Alice, Jim
Bob Dewitt, Alice Light, Jim Simons
```

Best,

[NO_TRAIN]::

Review the existing Get All Casings recipe and the linked pull-request discussion first, then compare their behavior with the examples in this issue. Define the recipe's casing behavior and add a separate operation for the requested input forms. It is done when the recipe produces the listed example outputs and integrates with CyberChef's operation list.

Written by the indexing model from the issue text.