bug: /mentorship/ad-hoc-timeline returns 500 when backend is unreachable (missing fallback)

[yingliu-data]

Bug Report

/mentorship/ad-hoc-timeline returns a 500 whenever the backend is unreachable, because the page has no static fallback (its sibling long-term page does).

• src/lib/api.ts:60-71 — the pageData fallback map has no 'mentorship/ad-hoc-timeline' key, and responses/adHocTimeLine.json exists but is never imported.
• src/pages/mentorship/ad-hoc-timeline.tsx:96-103 — getServerSideProps returns props.data = undefined when the fetch fails.

Reproduction

Backend down/misconfigured → fetchData returns { data: undefined } → getServerSideProps returns data: undefined → Next.js throws "Error serializing .data" → 500 page. The long-term-timeline page falls back gracefully in the same situation.

Severity

Medium

Potential Risk

• The ad-hoc timeline page hard-fails during any backend outage, instead of degrading to static content.

Suggested Fix

• Add a 'mentorship/ad-hoc-timeline' entry to the fallback map wired to responses/adHocTimeLine.json.
• Guard getServerSideProps so data is never undefined (return the fallback or a safe default).
• Add a test simulating a failed fetch and asserting the fallback renders.