fix: change model download path to models/ to avoid persistent storage mount hiding files

fix: create /data with correct permissions before downloading

chore: update model paths to point to /data/

Migrate from FLUX.1-schnell to FLUX.2-klein-base-4B

Fix HF_TOKEN injection during docker build by using BuildKit secrets mount

Install git in runtime stage to fix HF Space build

Initialize project files and updated hackathon tags