0.4.2

feat: update llama.cpp dependency and improve model loading

- Remove direct llama.cpp Swift package dependency in favor of
  pre-built xcframework
- Update LlamaFramework binary to latest version b7681
- Replace llama_load_model_from_file with llama_model_load_from_file
- Replace llama_new_context_with_model with llama_init_from_model
- Add vocab property to LlamaModel class and use llama_model_get_vocab
- Update token handling to use vocab instead of model for token operations
- Replace llama_n_ctx_train with llama_model_n_ctx_train
- Replace llama_token_is_eog with llama_vocab_is_eog
- Update llama_token_to_piece calls to use vocab parameter
- Replace llama_free_model with llama_model_free
- Add proper memory management with llama_get_memory and llama_memory_clear
- Update README.md package version from 0.4.0 to 0.4.2
- Add Vocab type alias in TypeAlias.swift
- Remove Package.resolved files
- Update project build configurations and package references

BREAKING CHANGE: The llama.cpp dependency is now provided as a
pre-built xcframework instead of source dependency.