• Review current tally summary and tally snapshot processing logic.
• Identify required changes to support the is_primary flag.
• Determine impact on data model, processing flow, and queries.
• Document findings and recommended approach.

AC

• Required changes for is_primary support are clearly identified.
• Impacted components and data flows are documented.
• Make sure there is no change when we send message to Kafka. Make sure there is no DTO change
• No code changes implemented in this card.
• Findings are reviewed and documented in Design doc.