Closes issue #5 (Dashboard | Update menu & page):
- Analytics content (heatmap, sparkline, token/cost/workflow/productivity
charts) moves into a new "Analytics" tab on the Dashboard page, alongside
the existing Monitor/Health tabs. The standalone Analytics page, its
/analytics route, and its sidebar menu entry are removed.
- The Kanban Board page, its /kanban route, and its sidebar menu entry are
removed entirely (page content deleted, not just hidden).
- Updated ARCHITECTURE.md, README.md, client/README.md, docs/API.md, and
the affected client tests/snapshots to match.
nntrivi2001
8ce20e8163