Firestore Security Rules Creation

[!IMPORTANT] Subagent Delegation vs. Direct Authoring

• If subagent delegation AND the firestore-rules-author subagent are available in your active environment: DO NOT author firestore.rules directly in the main agent. Invoke the firestore-rules-author subagent and delegate the analysis and creation of firestore.rules to it.
• If subagent delegation is unavailable (e.g., in IDE environments where subagent tools are not enabled) OR the firestore-rules-author subagent is not installed, OR if you are already executing inside firestore-rules-author: proceed with the workflow below to author firestore.rules directly.