Remove default value from organization_id column in authentication_events table

Summary

Remove the default value of 1 from the organization_id column in the authentication_events table. This is the final cleanup step after ensuring the application code properly populates the column.

Background

This is part of the effort to add organization_id as the sharding key for the authentication_events table (#561359 (closed)). After the application code has been updated and verified to correctly populate the organization_id column, the temporary default value can be safely removed.

Implementation Details

• Create a migration to remove the default value from the organization_id column
• Verify that all recent records have proper organization_id values (not just the default)
• Ensure the column remains NOT NULL (if applicable)

Acceptance Criteria

• Migration created to remove default value from organization_id column
• Verified that application code is correctly populating organization_id
• Verified in production that new records have proper organization_id values
• Migration tested locally

Related Issues

• Parent: #561359 (closed)
• Investigation: #553447 (closed)

Dependencies

• Requires completion of application code updates to store current organization
• Should only be done after verifying the application code is working correctly in production

Verification

Before removing the default value, verify:

• Application code has been deployed and running in production
• New authentication_events records have correct organization_id values
• No records are being created with NULL organization_id