feat(PBI-78): cost-analysis widget on insights page (#187)
* feat(PBI-78): cost-analysis data layer (T-902)
- New lib/insights/cost-analysis.ts with 5 query functions:
getCostKpi, getCostByDay, getCostByModel, getCostByKind, getCacheEfficiency
- Period type: 7d | 30d | 90d | mtd
- Cost formula reused from token-stats.ts (input + output + cache + thinking)
- Cache savings: cache_read_tokens × (input_price - cache_read_price) / 1M
- Plan: docs/plans/PBI-78-cost-analysis-widget.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
* feat(PBI-78): cost-analysis UI component (T-903)
- New app/(app)/insights/components/cost-analysis.tsx
- Period selector (7d/30d/90d/MTD) via URL ?period= with useTransition + router.replace
- KPI strip: total cost, avg per day, cache savings, top model
- 2x2 chart grid: daily cost (BarChart), per-model + per-kind (vertical BarCharts), cache efficiency (PieChart)
- Empty state for kpi.jobCount === 0
- Uses MD3 tokens (var(--chart-N), var(--status-done))
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
* feat(PBI-78): wire CostAnalysisCard onto insights page (T-904)
- Parse ?period= from searchParams (default 30d, validates against 7d/30d/90d/mtd)
- Parallel-fetch 5 cost queries via Promise.all alongside existing widgets
- New "Cost analyse" section between Sprint Health and Plan-quality
- Existing TokenUsageCard ("Token gebruik" section) stays as sprint detail
verify (lint+typecheck+test) and build pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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