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

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

server/api/library/stills/[id].get.ts

@@ -7,13 +7,26 @@ export default defineEventHandler(async (event) => {
   const still = getStill(owner, id)
   assertFolderAccess(event, still.folderId)
   const wantThumb = String(getQuery(event).thumb || '') === '1'
-  const path = wantThumb ? await stillThumbPath(owner, id) : stillPath(owner, still.id)
-  if (!path || !existsSync(path)) {
+  const original = stillPath(owner, still.id)
+
+  let path = original
+  if (wantThumb) {
+    path = await stillThumbPath(owner, id)
+    // Never fall back to the archive PNG/JPEG for ?thumb=1
+    if (!path || path === original || !existsSync(path)) {
+      throw createError({ statusCode: 404, statusMessage: 'Thumbnail not found' })
+    }
+  } else if (!existsSync(path)) {
     throw createError({ statusCode: 404, statusMessage: 'Image file is missing' })
   }
+
   const etag = fileEtag(path)
   setHeader(event, 'ETag', etag)
-  setHeader(event, 'Cache-Control', wantThumb ? 'private, max-age=86400, stale-while-revalidate=604800' : 'private, max-age=3600')
+  setHeader(
+    event,
+    'Cache-Control',
+    wantThumb ? 'public, max-age=86400' : 'private, max-age=3600'
+  )
   if (getHeader(event, 'if-none-match') === etag) {
     setResponseStatus(event, 304)
     return null