Memoize the Analytics period data selection and derived KPIs to cut chart re-renders

[1nonlypiece]

📌 Description

src/pages/Analytics.tsx recomputes the selected-period dataset and derived
metrics on every render, and the chart token sync via MutationObserver can
trigger extra renders. This issue memoizes the period selection and derived KPI
values so the recharts subtree only re-renders when inputs actually change.

🎯 Requirements and Context

• Wrap period-data selection and KPI derivations in useMemo keyed on period and
  tokens.
• Stabilize callback identities passed to chart children with useCallback.
• No change to displayed values; verify with render-count assertions.

🛠️ Suggested Execution

1. Fork the repo and create a branch

git checkout -b perf/analytics-memo

2. Implement changes

• Update src/pages/Analytics.tsx.
• Tests: extend src/pages/__tests__/Analytics.test.tsx asserting stable output
  and reduced re-computation.
• Docs: extend docs/PERFORMANCE.md.

3. Test and commit

• Run npm test.
• Cover edge cases: period switch recomputes once, theme change recomputes
  tokens only, identical inputs skip recompute.

Example commit message

perf: memoize Analytics period selection and derived KPIs

✅ Guidelines

• Minimum 95% test coverage on the new/changed lines.
• No change to displayed metrics.
• Timeframe: 96 hours.

🏷️ Labels

type-performance · area-frontend · MAYBE REWARDED · GRANTFOX OSS · OFFICIAL CAMPAIGN

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[Gbotemi-ojo]

@Gbotemi-ojo has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello maintainer,kindly assign this issue to me I can solve this bug free

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Gbotemi-ojo to this issue.

[drips-wave]

Congratulations, @Gbotemi-ojo! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @Gbotemi-ojo: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

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