docs: README output directory does not match actual behaviour

[CevenJKnowles]

Description

The README states generated files are written to the root directory:

"The tool will generate the following files in the root directory"

The actual output directory is output/ as specified in config.example.json:

"output_dir": "output"

Steps to Reproduce

Run the application with any valid job URL. Output files land in output/
not the root directory.

Suggested Fix

Update README to reflect output/ as the output directory.

Noted during testing in PR #11.