README.md: dependencies, build instructions for all three targets
(verified all six PRJ x CONFIG combinations build cleanly from a fresh
make clean, plus make clean's CONFIG scoping, default invocation,
incremental no-op rebuilds, and the install target), how to run each
binary, GPU acceleration usage, and a project-files overview.
CLAUDE.md's "Entry points" section still described main.cpp's old
CREATE_TEST/TRAIN_TEST behavior -- missed this on the earlier pass that
fixed the "Build" section's description of the same file.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016K8Gu7Qejd11JbdiHZqYAs
