PacketLLM 0.1.0

• Initial Release to CRAN.
• Provides an RStudio Gadget (run_llm_chat_app()) for interactive chat with OpenAI models (e.g., GPT-4o, GPT-4.1).
• Supports multiple, tabbed conversations.
• Allows uploading .R, .pdf, and .docx files as context for models supporting attachments.
• Enables setting the model, temperature, and system message per conversation (before the first message).
• Features asynchronous API calls to keep the R console responsive.
• Includes helper functions for managing conversation history and settings (create_new_conversation, get_active_chat_history, set_conversation_model, etc.).
• Requires an OPENAI_API_KEY environment variable for API access.
• Added basic unit tests using testthat.
• Added README.md and an introductory vignette (vignettes/PacketLLM-introduction.Rmd).