This commit introduces the `chrono` dependency to the project, enabling
the use of time-related functionalities. Additionally, it adds several
example files (`closure.myc`, `fib.myc`, `hof.myc`) to showcase the
language's features like closures, recursion, and higher-order
functions.
The `Cargo.lock` and `Cargo.toml` files have been updated to reflect the
new dependency. The `integration_test.rs` file now includes a test to
run all `.myc` files found in the `examples` directory, ensuring their
correctness. The `main.rs` file has also been updated to load and
display these examples in the UI.