Testing code assist tools for package maintenence

[bmeyers]

The changes in this PR were produced by prompting a "Claude Code" command-line harness, targeting a locally hosted LLM (Qwen3.6-27B-4bit), served with oLMX.

The PR addresses two issues of technical debt

1. All the functions in the Data I/O module have been depreciated for many releases. This PR removes the module and cleans up references and imports. I was aware of this issue, and prompted the command line system to work on this task
2. We had previously defined a [project.optional-dependencies] "dev" extra in the lint CI workflow, but dev was not defined in pyproject.toml. I was not previously aware of this issue, and the command line system surfaced the issue after a prompt to scan the code base for improvements.

Finally, this PR adds a CLAUDE.md file for directing automatic coding tools.

[cdeline]

Agree with the removal of the dataio and get_pvdaq_data functions if they are deprecated and no longer working. Maybe we can include some sort of connector to OpenEI data in the future as a todo item, but this makes sense for now. Everythign else looks fine and pytests are passing for me.