* feat: seed memory cache from pre-rendered routes at startup
Read vinext-prerender.json and pre-rendered HTML/RSC files at production
server startup to populate the MemoryCacheHandler. This ensures the first
request to any pre-rendered page is a cache HIT instead of triggering a
full re-render.
- Add seedMemoryCacheFromPrerender() in server/seed-cache.ts
- Add buildId, router, and trailingSlash to the prerender manifest
- Call seeding during App Router production server startup
- 11 unit tests covering ISR routes, static routes, dynamic routes,
trailingSlash, graceful degradation, and missing files
Closes#561
* fix: address review feedback on cache seeding PR
- Warn on corrupt manifest JSON instead of silent swallow
- Always serialize trailingSlash (typeof boolean, not truthiness)
- Populate setRevalidateDuration() for seeded entries so
Cache-Control headers are correct on first HIT
- Return seeded route count and log it at startup
- Add tests: corrupt JSON, missing buildId, FNV hash path,
revalidate duration tracking, return value assertions
Addresses review comments on #645.