docs: simplify README organization (#167)

## Summary

Reorganizes the README so installation and common workflows are easier
to find.

- Adds collapsible CLI and Programmatic installation paths, with Rust,
Python, and JavaScript subsections.
- Separates quick starts from installation and groups the CLI reference,
configuration, and compatibility material.

## Checks

- Checked Markdown details tags, code fences, and internal heading
anchors.
- Ran `git diff --check`.

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Signed-off-by: cpendery <cpendery@vt.edu>