- feature: execute from code files

[agallardol]

Refactor code from string with CodeFiles struct

1. Added a new CodeFiles struct to represent the code files for a tool, including a map of file paths to contents and an entrypoint file path. This replaces passing around a single code string.

2. Updated the DenoExecutionStorage struct to take a CodeFiles instead of a code string in its constructor. It now writes out all the files in CodeFiles when initializing the storage directories.

3. Updated the DenoRunner to take a CodeFiles instead of a code string when running. It passes this through to the DenoExecutionStorage.

4. Updated tests to construct CodeFiles structs instead of passing code strings directly. For example:

Example

    let main_code = r#"
        import { helper } from "./helper.ts";
        import { data } from "./data.ts";
        
        function run() {
            return helper(data);
        }
    "#;

    let helper_code = r#"
        export function helper(input: string) {
            return `processed ${input}`;
        }
    "#;

    let data_code = r#"
        export const data = "test data";
    "#;

    let code_files = CodeFiles {
        files: HashMap::from([
            ("main.ts".to_string(), main_code.to_string()),
            ("helper.ts".to_string(), helper_code.to_string()),
            ("data.ts".to_string(), data_code.to_string()),
        ]),
        entrypoint: "main.ts".to_string(),
    };

    let tool = Tool::new(code_files, Value::Null, None);
    let result = tool.run(None, Value::Null, None).await;
    
    assert!(result.is_ok());
    assert_eq!(result.unwrap().data, "processed test data");