frontend: audit & migrate key Streamlit views to React pages (archive legacy/streamlit)

[ayushkrtiwari]

Goal

Port important interactive dashboards that exist in legacy/streamlit into the cauweb React/TS frontend (or archive safely if deprecated). README references Streamlit in legacy/ folder. :contentReference[oaicite:1]{index=1}

Tasks

• Inventory Streamlit pages & features in legacy/streamlit/ (list components: charts, controls, upload flows).
• For each feature, map to a React page or mark for deprecation (decide: migrate vs archive).
• Implement React equivalents using the existing cauweb design system (charts, controls, export).
• Add data endpoints (REST/WS) where Streamlit used local Python functions; document the API contract.
• Add a migration README: which features moved, which are archived, and how to run old Streamlit (if needed).

Acceptance criteria

• Inventory doc exists and all high-value Streamlit features are either migrated to React pages or clearly archived.
• No user-facing feature loss without an explicit deprecation note in README.