Agent Skills: feature-flags

Feature flag implementation, management, and best practices for gradual rollouts. Use when user mentions "feature flag", "feature toggle", "feature gate", "canary release", "percentage rollout", "A/B testing", "LaunchDarkly", "Unleash", "Flagsmith", "gradual rollout", "kill switch", "dark launch", "trunk-based development with flags", or controlling feature visibility in production.