New /analytics route: token usage dashboard with aggregate summary,
per-session breakdown, context window stats, and per-category token
distribution. Data served from existing agent_sessions + tool_cost_stats.
New /results route: browsable archive of orchestrator flow runs and
arena battles. Two-tab layout (Analysis Runs / Arena Battles) using
existing API endpoints (no new backend).
Sidebar gains Results (ScrollText icon) and Token Analytics (BarChart3
icon) nav buttons above Settings.