Function register_tool_functions 

pub fn register_tool_functions(
    lua: &Lua,
    sandbox: Arc<dyn SandboxPolicy>,
) -> Result<(), LuaError>

Registers all tool functions in the Lua orcs table.

The sandbox controls which paths are accessible. All file operations validate paths through the sandbox before any I/O.

Adds: orcs.read, orcs.write, orcs.grep, orcs.glob, orcs.mkdir, orcs.remove, orcs.mv

Errors

Returns error if function registration fails.