[NOTICKET] feat(knowledge,analysis): add deletion confirmation, duplicate-name guard, and unusable-analysis lockout

feat: fetch and render charts for chat answers via /api/v1/charts

feat: sort analyses by updated_at, render data_used in traceability

fix: keep suggested questions reachable, simplify sources control, fix dark-mode logo contrast

fix: resizable report sidebar, stable chat layout, guided empty state

fix: handle failed AI message persistence per updated Go contract

fix: update traceability endpoint, remove retry logic, and fix report stale version

fix: improve analysis chat rendering, scroll, and traceability persistence

fix: stabilize analysis chat rendering and traceability

feat: refine analysis workspace navigation and theming

feat: polish workspace navigation and PWA branding

feat: implement dual-backend analysis workspace UX