Add per-user library settings, folder passwords, and a still picker.

Settings manages folders, thumbnail defaults, and passwords for the signed-in account, and choosing an image now browses saved stills instead of only the desktop file dialog.

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

server/api/library/unlock.post.ts

@@ -1,12 +1,11 @@
 export default defineEventHandler(async (event) => {
-  const body = await readBody<{ password?: string }>(event)
+  const { owner } = assertLibraryOwner(event)
+  const body = await readBody<{ password?: string; folderId?: string }>(event)
   const password = String(body?.password || '')
   if (!password) {
     throw createError({ statusCode: 400, statusMessage: 'Password is required' })
   }
-  if (!(await verifyLibraryPassword(password))) {
-    throw createError({ statusCode: 401, statusMessage: 'Incorrect library password' })
-  }
-  setLibraryUnlock(event, currentPasswordVersion())
+  const unlocked = await unlockMatchingFolders(owner, password, body?.folderId)
+  setFolderUnlocks(event, Object.fromEntries(unlocked.map(folder => [folder.id, passwordVersion(folder.passwordHash)])))
   return publicLibrary(event)
 })