Campaign CRUD API with cascading delete across all campaign-scoped
tables, a systems endpoint to seed the create-campaign form, active
campaign state wired to the sidebar chaos factor, and a campaign
management view for creating/switching/deleting campaigns.
Sidebar with collapsible nav, dark/light theme tokens, and
localStorage-backed state for collapse/theme/active view.
Chaos factor UI is display-only pending Phase 3 backend wiring.