Returns the path to the SAFE config file for the given project.

Finds the longest common directory prefix shared by all paths.

Each path is split into segments; shared leading segments are rejoined. Returns an empty string when paths is empty or no segments are shared.

Generates the SAFE JSON config string from the live Mix project.

Returns {:ok, json_string}. Does not write to disk.

Reads .safe/config.json from the project directory.

Returns {:ok, json_string} or {:error, {:config_read_error, reason}}.

Writes json to .safe/config.json in the project directory.