feat(frontend): portfolio analytics dashboard with performance metrics

[samjay8]

Summary

Build a comprehensive analytics dashboard showing portfolio performance metrics, yield history, and risk analysis for lenders.

Problem

Lenders have no visibility into their portfolio performance over time. They can see current positions but not historical yields, risk exposure, or diversification metrics.

Requirements

• Total portfolio value (USD equivalent) over time
• Yield earned per position and aggregate
• Risk exposure by invoice status (Financed, Repaid, Defaulted)
• Diversification metrics (number of invoices, currencies, originators)
• Historical charts (30d, 90d, 1y, all-time)
• Export to CSV/PDF
• Shareable portfolio snapshot

Technical Details

• Data from indexer aggregate tables (Task 13)
• Charts via recharts or @nivo library
• Historical data from Soroban event history
• PDF export via @react-pdf/renderer

Acceptance Criteria

• Dashboard shows all key metrics
• Charts render with historical data
• Export works for CSV and PDF
• Loading states for async data
• Responsive on mobile
• Shareable snapshot link

Related Issues

• Related to: Portfolio dashboard API for lenders #14 (public /stats dashboard page)
• Related to: feat(frontend): USD-equivalent portfolio totals across currencies #182 (USD-equivalent portfolio totals)

[KarenZita01]

Hi I'd like to work on this issue. I have experience in frontend, backend and contracts and can also deliver a clean & meaningful pr. Thanks

[grantfox-oss]

🦊 GrantFox — @KarenZita01 has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #225)
2. Your PR will be reviewed by the Stellar-VaultLink maintainers

Good luck! Track your progress on GrantFox.