- Split 1189-line runtimes-page.tsx into focused sub-components (list, detail, ping, usage, 5 chart files, shared UI, utils)
- Add useRuntimeStore zustand store for shared runtime state across pages (agents page now uses it too)
- Add 7d/30d/90d time range selector to usage charts
- Add full-stack runtime delete: SQL query, Go handler, API route, frontend with confirmation dialog
- Remove unused daemon:heartbeat WS listener (server never broadcasts it)