chore: remove frontmatter injection from deploy workflow, add frontmatter directly to README

ci: inject HF Spaces frontmatter into README at deploy time

chore: rename HF owner HlexNC → arudaev across all references

Restore src/data package, fix HF Space bootstrap, improve Kaggle/CI wiring

Fix CI, unblock Kaggle training dispatch, upgrade demo app for HF Spaces

Initial project scaffold: CheXVision — Chest X-Ray Pathology Detection