perf: reduce dev compile times

[JLRansom]

Summary

• Fix double analytics fetch (AnalyticsPanel.tsx): Replace cancelled boolean flag with AbortController so React StrictMode's double-invocation of useEffect aborts the first in-flight request instead of sending two parallel HTTP calls.
• Lazy-load recharts (AnalyticsCharts.tsx + AnalyticsPanel.tsx): Extract all five chart blocks (BarChart, LineChart, AreaChart, and the meetings chart) into a new AnalyticsCharts component loaded via next/dynamic with ssr: false. Recharts is now excluded from the initial bundle and compiled only when the charts pane is first rendered.
• Add loading skeletons to dynamic boundaries (MeetingsPanelLoader.tsx, MeetingView.tsx): Add loading fallback UI to the existing dynamic() calls for MeetingsPanel and MeetingScene so users see a placeholder immediately instead of a blank area during chunk download.

Test plan

• Visit a project analytics page — charts render correctly after data loads
• Switch time range — only one fetch fires (verify in Network tab; no duplicate requests)
• Navigate to Meetings panel — loading skeleton shows briefly before panel appears
• Open a meeting — "Loading scene…" placeholder shows while Three.js chunk loads
• npx tsc --noEmit passes with no new type errors

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