- Added a `DecodeAsync` overload which runs the work in a task
 - Replaced some `NativeHandle` usage in `BatchedDecoding` with higher level equivalents.
 - Made the `LLamaBatch` grow when token capacity is exceeded, removing the need to manage token capacity externally.

- `AntipromptProcessor` accepts chunks of text and returns a value indicating if any antiprompt has been detected.
 - `StreamingTokenDecoder` decodes tokens into text, maintaining some internal state to handle single characters which are encoded as multiple tokens.

Added tests for these classes and updated StatelessExecutor to use them.

Removed most DeTokenize methods, marked the rest as obsolete (should always use a `StreamingTokenDecoder`).

* Added the low level bindings to beam search.