Replace hardcoded global API URL variables with getter functions that check the R_BASE_URL environment variable, falling back to the static defaults. Introduce a joinpath utility in utils.h to safely concatenate a base URL with a path segment, handling trailing slashes and leading path slashes. Remove conditional compilation blocks for RD and OLLAMA backends, consolidating all API URL logic into the new get_completions_api_url and get_models_api_url functions. Update all call sites in openai.h to use the new getter functions instead of direct global variable access.
- Remove the initial commit placeholder progress message from Makefile
- Add `!tools` command to REPL that prints available tools descriptions
- Include tools.h header and integrate tools_descriptions() function
- Switch default RD backend from DeepInfra/Llama to Anthropic/Claude models
- Update advanced_model and fast_model to claude-3-5-haiku-20241022
- Change completions_api_url to Anthropic API endpoint
- Enable verbose mode by default (is_verbose = true)
- Update README to reflect new Claude/Ollama focus and remove old download links
Introduce conditional compilation via OLLAMA preprocessor flag to switch between OpenAI and Ollama API endpoints, model names, and URLs. Add `build_free` and `run_free` Makefile targets for the Ollama variant. Enhance REPL with `!models` command to list available models, improve error handling in `openai_process_chat_message`, and fix history line addition logic.
