Add paginated library JSON and dedicated still thumbs that never stream archive masters.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/api/library/clips/[id]/thumb.get.ts

@@ -13,7 +13,7 @@ export default defineEventHandler(async (event) => {
   }
   const etag = fileEtag(path)
   setHeader(event, 'ETag', etag)
-  setHeader(event, 'Cache-Control', 'private, max-age=86400, stale-while-revalidate=604800')
+  setHeader(event, 'Cache-Control', 'public, max-age=86400')
   if (getHeader(event, 'if-none-match') === etag) {
     setResponseStatus(event, 304)
     return null