CI/CD Group Analytics: Create empty dashboard page behind `ci_group_analytics` feature flag
## Summary Create a new page for the CI/CD Group Analytics dashboard, gated behind the `ci_group_analytics` feature flag. The page should render an empty shell (no content yet) that will be progressively filled in by subsequent issues. ## Acceptance Criteria - A new route exists for the group-level CI/CD analytics dashboard - The page is only accessible when the `ci_group_analytics` feature flag is enabled - The page renders without errors (empty state is acceptable) - The feature flag `ci_group_analytics` is documented and registered ## Notes - This is the foundational scaffold for the entire CI/CD Group Analytics feature - All subsequent FE and BE work for this feature should also be gated behind `ci_group_analytics`
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