- add ContextMenu component with click-outside/Escape dismiss, align prop, and danger variant
- replace EnvironmentsPage table with responsive card grid
- add cog button to each card opening a context menu with view and delete actions
- add EnvironmentDetailPage at /environments/:id with meta grid, URLs card, and delete
- add Breadcrumbs to all pages; detail page uses two-item trail with delete button inline
- add Table stories for pagination and Timestamp column
