Sets up, manages, queries, and configures Cloud Firestore databases (Standard/Enterprise edition), including data modeling, security rules, indexes, and SDK integrations (Web, Admin, Python, iOS, Android, Flutter). Use when adding or migrating app databases, creating/listing Firestore databases, defining data models/indexes, writing SDK queries, or integrating Firestore SDKs. For authoring or modifying Firestore Security Rules (firestore.rules), delegate to the firestore-rules-author subagent if subagent delegation is available, or use firestore-rules-creation otherwise. Don't use for Data Connect, BigQuery, or standalone Hosting, Auth, Storage/GCS, Crashlytics, or Functions tasks.