README still describes the pre-rename "PRD" terminology (v4.0.0), while versions/TheAlgorithm_Latest.md is at v6.3.0 and uses "ISA"

The top-level `README.md`'s "How It Works" section still refers to the artifact as a "PRD" and cites v4.0.0 doctrine:

https://github.com/danielmiessler/TheAlgorithm/blob/main/README.md

`versions/TheAlgorithm_v4.1.0.md` shows this was intentionally renamed to "ISA" (with reasons given), and the currently-pinned spec, `versions/TheAlgorithm_Latest.md`, is at v6.3.0 and uses "ISA" throughout:

https://github.com/danielmiessler/TheAlgorithm/blob/main/versions/TheAlgorithm_Latest.md
https://github.com/danielmiessler/TheAlgorithm/blob/main/versions/TheAlgorithm_v4.1.0.md

The README appears to predate the rename and hasn't been updated to match the current pinned version — a new reader landing on the README first would learn outdated terminology. Happy to open a PR syncing the README to Latest.md's terminology if useful.

Compare the top-level README.md "How It Works" section with versions/TheAlgorithm_Latest.md and the rename rationale in versions/TheAlgorithm_v4.1.0.md. Update the README's outdated "PRD" terminology and v4.0.0 reference to match the currently pinned ISA terminology and version, then verify the section is consistent with Latest.md.

Written by the indexing model from the issue text.