chore: add workspace metadata and crate READMEs for publishing

Add license, authors, repository, documentation, keywords, categories,
and readme fields to all crate Cargo.toml files. Add crate-level README
files for documentation.

Co-Authored-By: claude-flow <ruv@ruv.net>

rust-port/wifi-densepose-rs/crates/wifi-densepose-nn/Cargo.toml

@@ -9,6 +9,7 @@ documentation.workspace = true
 keywords = ["neural-network", "onnx", "inference", "densepose", "deep-learning"]
 categories = ["science", "computer-vision"]
 description = "Neural network inference for WiFi-DensePose pose estimation"
+readme = "README.md"
 
 [features]
 default = ["onnx"]