feat(github): add AbortController timeout to fetchWithRetry with per-endpoint defaults (JhaSourav07#423)

## Description

Fixes JhaSourav07#273 

- Added two constants `GRAPHQL_TIMEOUT_MS` and `REST_TIMEOUT_MS` for the
default timeouts
- Added optional `timeoutMs` parameter to `fetchWithRetry` for `per-call
override`
- Added `AbortController` with `setTimeout` — fires after the resolved
timeout and aborts the fetch
- Passed `signal: controller.signal` into the fetch options
- `clearTimeout` called in both success and error paths to avoid memory
leaks
- `AbortError` is caught specifically and throws a clean typed message
"GitHub API request timed out after Xs"
- Recursive retry calls pass `timeoutMs` through so each attempt gets
its own fresh timeout window
- All existing retry logic for network errors and 5xx remains completely
intact
- No other files need changes — `route.ts` error SVG already catches all
Error instances and renders them cleanly.

## Pillar

- 🛠️ Other (Bug fix, refactoring, docs)

## Visual Preview

- With `GRAPHQL_TIMEOUT_MS` and `REST_TIMEOUT_MS` set to a very small
value like `1`:
<img width="508" height="313" alt="Screenshot 2026-05-24 at 8 50 32 PM"
src="https://github.com/user-attachments/assets/34f91c6c-2b64-4855-abc4-87c7f6b29c2b"
/>
<img width="516" height="210" alt="Screenshot 2026-05-24 at 8 50 52 PM"
src="https://github.com/user-attachments/assets/4789b216-c796-48de-9faf-6927535ef5f5"
/>

- With `GRAPHQL_TIMEOUT_MS` and `REST_TIMEOUT_MS` set to appropriate
values like `8000` & `5000` respectively:
<img width="668" height="546" alt="Screenshot 2026-05-24 at 8 51 35 PM"
src="https://github.com/user-attachments/assets/44d7383d-e2bd-4b19-b4cf-71fbefe7a3bb"
/>


## Checklist before requesting a review:

- I have read the `CONTRIBUTING.md` file.
- I have tested these changes locally
(`localhost:3000/api/streak?user=YOUR_USERNAME`).
- I have run `npm run format` and `npm run lint` locally and resolved
all errors.
- My commits follow the Conventional Commits format.
- I have starred the repo.
- I have made sure that i have only one commit to merge in this PR.
- The SVG output matches the CommitPulse "premium quality" aesthetic
standard.

Author: JhaSourav07

lib/github.ts

@@ -13,35 +13,51 @@ const MAX_RETRIES = 3;
 const BASE_DELAY_MS = 500;
 const CONTRIBUTION_MILESTONES = [1, 10, 100, 250, 500, 1000];
 const STREAK_MILESTONES = [3, 7, 30, 100];
+const GRAPHQL_TIMEOUT_MS = 8000; // 8s for GraphQL endpoint
+const REST_TIMEOUT_MS = 5000; // 5s for REST endpoints
 
-/**
- * Wraps fetch with exponential backoff retry logic.
- * Retries ONLY on network errors, 429 Too Many Requests, and 5xx server errors.
- * Returns immediately for all other statuses (2xx success, 3xx redirects, 4xx client errors).
- */
 export async function fetchWithRetry(
   url: string,
   options: RequestInit,
-  attempt = 0
+  attempt = 0,
+  timeoutMs?: number
 ): Promise<Response> {
+  // Determine default timeout based on endpoint type if not explicitly provided.
+  // GraphQL calls carry a larger payload and need a slightly longer window.
+  const resolvedTimeout =
+    timeoutMs ?? (url.includes('graphql') ? GRAPHQL_TIMEOUT_MS : REST_TIMEOUT_MS);
+
+  // Each retry attempt gets a fresh AbortController so the timeout window
+  // resets per attempt — not cumulative across the entire retry chain.
+  const controller = new AbortController();
+  const timeoutId = setTimeout(() => controller.abort(), resolvedTimeout);
+
   let res: Response | null = null;
   try {
-    res = await fetch(url, options);
+    res = await fetch(url, { ...options, signal: controller.signal });
   } catch (err) {
+    clearTimeout(timeoutId);
+    // AbortError means the timeout fired — throw a clear typed message.
+    if (err instanceof Error && err.name === 'AbortError') {
+      const seconds = resolvedTimeout / 1000;
+      throw new Error(`GitHub API request timed out after ${seconds}s`);
+    }
     // Network error — retry if attempts remain, otherwise rethrow
     if (attempt >= MAX_RETRIES) throw err;
     const delay = BASE_DELAY_MS * Math.pow(2, attempt);
     await new Promise((resolve) => setTimeout(resolve, delay));
-    return fetchWithRetry(url, options, attempt + 1);
+    return fetchWithRetry(url, options, attempt + 1, timeoutMs);
   }
 
+  clearTimeout(timeoutId);
+
   // Only retry on 429 or 5xx — all other statuses are returned immediately
   const shouldRetry = res.status === 429 || res.status >= 500;
   if (!shouldRetry || attempt >= MAX_RETRIES) return res;
 
   const delay = BASE_DELAY_MS * Math.pow(2, attempt);
   await new Promise((resolve) => setTimeout(resolve, delay));
-  return fetchWithRetry(url, options, attempt + 1);
+  return fetchWithRetry(url, options, attempt + 1, timeoutMs);
 }
 
 const GITHUB_GRAPHQL_URL = 'https://api.github.com/graphql';