- New /models page in left nav (after Analytics)
- New /api/analytics/models endpoint with per-model token/cost/session
breakdown, cache read/reasoning tokens, tool calls, avg tokens/session,
and capabilities from models.dev (vision/tools/reasoning/context window)
- Model cards with stacked token distribution bar, capability badges,
provider badges, cost info, and relative time
- Summary stats bar (models used, total tokens, est. cost, sessions)
- Period selector (7d/30d/90d) with refresh
- i18n support (en + zh)
