Allow prompt-only writing styles

I would love the ability to create a writing style using only a custom prompt, without having to upload example documents.

In practice, I often start with examples to bootstrap a style, but then heavily refine and stabilise the prompt until it fully encodes the behaviour I want. At that point, the original examples no longer reflect the style and may even introduce unintended bias if reused later.

When creating a second version or variant of an existing style, it would be extremely useful to:

• Duplicate or paste an existing style prompt verbatim

• Skip the requirement to upload example texts

This would make style versioning, experimentation, and maintenance much cleaner for advanced users, while still keeping example-based creation as the default path.