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and hasn't been updated to match the current pinned version — a new reader landing on the README first would learn outdated terminology.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 Update the README's outdated "PRD" terminology and v4.0.0 reference to match the currently pinned ISA terminology and version, then verify the section is consistent with Latest.md.

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