Preserves Andrew Kensler's original card.cc verbatim and adds:
- CMakeLists.txt building both the original and a de-obfuscated
variant (card_explained.cc) that produces a visually identical render
- A heavily annotated rewrite explaining the vector ops, ray-sphere
intersection, soft shadows, depth of field, and reflection recursion
- Rendered sample output (docs/aek.png) embedded in the README
- CLAUDE.md establishing the "never modify card.cc" rule for future work
