Update .gitignore: allow data/ for HuggingFace dataset files

.gitignore

@@ -1,16 +1,3 @@
-# Data directories (large, downloaded)
-data/
-exports/
-
-# Experiment results & runtime logs (generated, large)
-results/
-logs/
-
-# Database files
-*.db
-*.sqlite
-*.sqlite3
-
 # Python
 __pycache__/
 *.py[cod]
@@ -35,7 +22,7 @@ venv/
 .idea/
 .vscode/
 
-# Claude Code local settings (contain tool permissions and local paths)
+# Claude Code local settings
 .claude/
 
 # Testing
@@ -43,11 +30,16 @@ venv/
 .coverage
 htmlcov/
 
-# Internal planning documents (not for public release)
+# Internal planning documents
 research/
 NeurIPS_DB_Track_Research.md
 
-# Binary files (PDFs) — not suitable for git/HuggingFace datasets
+# Database files (too large for git)
+*.db
+*.sqlite
+*.sqlite3
+
+# Binary files (PDFs)
 paper/main.pdf
 paper/*.aux
 paper/*.bbl
@@ -56,3 +48,10 @@ paper/*.log
 paper/*.out
 paper/missfont.log
 paper/figures/*.pdf
+
+# Runtime logs and internal audit artifacts
+logs/
+results/
+exports/reload_*.log
+exports/pubchem_qc_*
+exports/pubchem_strict_audit_*