Initialize catalog structure and product schema

docs/field-reference.md

@@ -0,0 +1,33 @@
+# Catalog Field Reference
+
+## Required Fields
+
+### `catalog_version`
+
+Catalog record format version.
+
+Current value:
+
+```json
+1
+
+Create a `.gitignore`:
+
+```bash
+cat > .gitignore <<'EOF'
+# Generated exports
+/exports/*
+!/exports/.gitkeep
+
+# Generated indexes
+/indexes/*
+!/indexes/.gitkeep
+
+# Local and temporary files
+*.tmp
+*.bak
+*.log
+.DS_Store
+Thumbs.db
+.vscode/
+.idea/