[FE-42] Set up fetch-based API client with JWT handling and auto refresh-on-401

[mftee]

Overview

There is no API client of any kind in the frontend yet — app/ contains only a placeholder layout and page. Every subsequent page needs a single, consistent way to call the backend.

Tech

Use the native fetch API wrapped in a small typed client. No axios/TanStack Query — neither is currently installed, and this scope doesn't need them.

Acceptance Criteria

• Create lib/api-client.ts exporting a request(path, options) helper that reads NEXT_PUBLIC_API_URL, attaches the JWT from the auth context (depends on FE-43) as a Bearer header, and parses JSON responses
• On a 401 response, attempt a silent refresh via POST /auth/refresh once; if refresh also fails, clear the session and redirect to /login
• Typed error handling: non-2xx responses throw a typed ApiError with status and message extracted from the backend's error shape
• Unit tests (jest, already configured) covering success, 401-then-refresh-success, and 401-then-refresh-failure paths

[elcabasa]

Hello Dear, I would like to take on the task of building the foundation for our backend communications. My Plan:Create Core Client: Build lib/api-client.ts using the native fetch API. It will automatically attach the JWT Bearer token, pull from NEXT_PUBLIC_API_URL, and return typed responses.Implement Silent Refresh: Handle 401 errors by attempting a single silent token refresh via POST /auth/refresh. On failure, it will wipe the session and route the user back to /login.Add Typed Error Handling: Create a dedicated ApiError class to cleanly capture non-2xx status codes and parse backend error shapes.Write Unit Tests: Deliver full Jest coverage handling success patterns, successful silent token refreshes, and complete refresh failures.I have extensive experience building robust, pure-JS API wrappers with clean error boundaries. Please assign this issue to me! Best regards,

[KuchiMercy]

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I'd like to work on this issue. Kindly assign.

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