Adds dimension-search crop recovery that tries candidate original sizes
to reconstruct the embed grid, and fixes test imports for GenericImageView.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Implements DCT-based steganography module that hides 256-bit secrets in
JPEG luminance channel using Quantization Index Modulation (QIM) with
redundant copies and majority voting for reliable extraction.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
