Document indexer contract and add non-blocking backend status banner

[pharuq411]

Summary

Document indexer contract and add non-blocking backend status banner

What was solved

#11 — Document the frontend/backend indexer contract and add a connection health check

Document the frontend/backend indexer contract (endpoints, port topology, backend repo link) in the README, and add a non-blocking BackendStatusBanner that runs a startup health check against the indexer and displays the configured URL when unreachable, wired into App.tsx.

Addressed:

• Changed: src/components/BackendStatusBanner.tsx, src/api.ts
• Document in README the /api/* endpoints the frontend consumes and the expected octraban_backend indexer on :3001, including port topology (API :3000, indexer :3001).
• Add a lightweight startup/connection health check against the backend health endpoint.
• Show a clear, non-blocking banner when the indexer is unreachable, including the configured URL.

Changes

• src/components/BackendStatusBanner.tsx (modify)
• src/api.ts (modify)

Approach

1. Read README.md, src/App.tsx, and src/api.ts to match existing structure, base URL config, and API client conventions.
2. Add a README section documenting the frontend/backend contract: /api/* endpoints consumed, port topology (API :3000, indexer :3001), and a link to the octraban_backend repository in the setup section.
3. Create src/components/BackendStatusBanner.tsx that runs a startup health check via the shared API client and renders a non-blocking banner with the configured URL when the indexer is unreachable, hidden on success.
4. Wire BackendStatusBanner into src/App.tsx without altering existing layout or unrelated logic.
5. Verify the health check uses the shared client (mockable in tests) and reuses the existing configured indexer URL rather than a new env var or hardcoded value.

Issues

Closes #11

[vercel]

@pharuq411 is attempting to deploy a commit to the Prisca's projects Team on Vercel.

A member of the Team first needs to authorize it.