- Fixed multiple enumeration
 - Fixed newline penalisation

ModelsParams record class

- Used those methods to add a `Clone` method to SafeLLamaContextHandle
 - Simplified `LLamaContext` by using the new methods
 - Sealed `LLamaContext` and `LLamaEmbedder`

- Passing encoding in the `IModelParams`, which reduces how often encoding needs to be passed around

- Removed some unnecessary `ToArray` calls
 - Initial pass on LLamaStatelessExecutor, the context overflow management is broken but I think I found where it's ported from

- Converted `SafeLLamaContextHandle` to take a `ReadOnlySpan` for Eval, narrower type better represents what's really needed

- Integrated grammar into sampling
 - Added a test for the grammar sampling

- sealed some classes not intended to be extended

- Sanity checking that weights are not disposed when creating a context from them
 - Further simplified `Utils.InitLLamaContextFromModelParams`

The biggest single change is renaming `LLamaModel` to `LLamaContext`