Break down cards.js

[hackertron]

src/data/cards/
├── proof-systems.js # ZK-SNARKs, ZK-STARKs, Bulletproofs, etc.
├── circuit-languages.js # Circom, Noir, Cairo, etc.
├── zk-rollups-scaling.js # ZK-Rollups, Validium, zkEVM, etc.
├── privacy-applications.js # Private Transactions, Semaphore, etc.
├── identity-solutions.js # ZK Identity, Anonymous Credentials, etc.
├── index.js # Aggregates all cards and exports getCardById
└── README.md # Instructions for adding new cards