Events page: per-row trend sparklines (#187)

[unjica]

Summary

• Add batch fetchSparklinesForEventNames on grouped GET /api/events — one query for all visible event names, bucketed over the active metrics/list window (no N+1)
• Wire Trend column with MiniSparkline in the grouped events table (mirrors errors Errors page: error types, stacked chart, and sparklines #182 pattern)
• Unit tests for resolveEventSparklineWindow and sparkline serialization

Approach

Reuses errors sparkline infrastructure (chooseTimeRangeBucket, generateOverviewChartBuckets) but keys series by event name instead of error group id. Sparkline window follows resolveEventCountRangeBounds / metricsUntil enrichment — same window as in-range counts and summary KPIs.

Test plan

• pnpm lint && pnpm test && pnpm build
• Bugbot review vs develop — no findings
• Open Events page with default (all-time) range — Trend column shows 7-day sparklines per row
• Switch to 24h / 7d / custom range — sparklines rescope to selected window
• Apply app/environment/platform/release filters — sparklines respect filters
• Verify empty/low-volume rows show em-dash placeholder

Closes #187

Follow-ups for #188

• Auto-captured vs Custom badge taxonomy on event names (separate from sparklines; no API changes needed here)

Made with Cursor