Control SPP dark launch to public projects using a FF

Problem to Solve

We need a controlled mechanism to safely test Secret Push Protection (SPP) enablement for all public projects without impacting system performance. Currently, there's no way to gradually roll out SPP to the large volume of public projects while monitoring the impact on the Secret Detection Service (SDS). A dark launch approach is needed to validate that SDS can handle the increased traffic load before fully enabling the feature.

Implementation Plan

1. Add Feature Flag

• Create feature flag secret_detection_enable_spp_for_public_projects to control SPP enablement
• Configure flag to route SPP requests through SDS deployed to runway instead of the SDS gem

2. Implement Dark Launch Logic

• Modify SPP logic to check the feature flag for public projects
• When flag is enabled, route secret detection through SDS service
• Ensure dark launch doesn't add extra load to the existing SDS gem