chore: remove unused data_dir / DATA_DIR (Storage Bucket dependency)

fix(docker): remove HEALTHCHECK to let HF Spaces use its own mechanism

refactor(docker): remove in-container Neo4j, connect to external GCP Neo4j

fix(neo4j): move data dirs from /data (S3 FUSE) to /tmp (local)

debug(spaces): HEALTHCHECK + neo4j logs to stdout for HF health check diagnosis

refactor(extractor): remove heuristic fallback, require OpenAI API key

fix(neo4j): use /data for persistent storage, chown fallback to chmod 777

refactor(docker): switch to python:3.11-slim base, install neo4j via APT

fix(neo4j): bypass entrypoint, write neo4j.conf directly, start binary via supervisord

fix(docker): add git for HF Spaces build pipeline

fix(neo4j): redirect data dirs to /tmp to avoid HF Spaces /data permission issue

fix(docker): upgrade pip before installing requirements

fix(docker): remove --break-system-packages unsupported by pip in base image

feat: implement CC-RAG prototype with Neo4j, FastAPI, React