Add file path completion support alongside existing command completion in the readline-based input system. Include <glob.h> header and implement line_file_generator function that uses glob pattern matching to suggest file paths based on partial input. Modify line_command_completion to detect file path context (non-command input after start position) and delegate to the new file generator, enabling tab-completion of filenames and directories in the shell-like interface.
Implement a new `tool_function_bash` that executes shell commands via `popen` and captures their output into a dynamically allocated buffer. Register the corresponding `tool_description_bash` JSON schema and include it in the `tools_descriptions` array alongside the existing HTTP GET tool. Also change the history file path from `~/.calpaca_history` to `.r_history` and remove the redundant `read_history` call before adding new history entries.
Add initial project structure including .gitignore for build artifacts,
Makefile with gcc build and run targets, README placeholder, cgi-bin
directory with gpt.py and gpt_template.html, and core C headers for
chat, http, line input, markdown rendering, and messages.
