- Made `NativeApi` into a `static class` (it's not intended to be instantiated)
- Moved `LLamaTokenType` enum out into a separate file
- Made `LLamaSeqId` and `LLamaPos` into `record struct`, convenient to have equality etc
- Removed all `record struct` uses in native code
- Removed usage of `readonly` in native structs
Minor fix:
- Added sequential layout to `LLamaModelQuantizeParams`