Initial release of CryptoAnalysis.jl — classical cryptanalysis and cipher-breaking toolkit.

Features:

• Frequency analysis (single char, bigram, trigram)
• Index of coincidence for cipher type detection
• Kasiski examination for key length estimation
• Caesar cipher encrypt/decrypt/break
• Vigenère cipher encrypt/decrypt/break
• XOR analysis with single-byte and repeating-key breaking
• Shannon entropy calculation
• Chi-squared statistical testing
• Hamming distance (bytes and strings)
• English plaintext scoring and detection
• 133 tests