• Update tally processing logic to identify the primary row when creating new tally summaries.
• Set is_primary = true for the primary tally snapshot record.
• Ensure non-primary rows default to is_primary = false and are not affected.
• Maintain consistency with existing tally summary creation flow.

Acceptance Criteria

• Primary tally snapshot is correctly identified during processing.
• is_primary is set to true only for the primary row.
• All non-primary rows have is_primary = false.
• No regressions in existing tally processing behavior.
• Unit and component tests validate the new logic.