A file opened without a File System Access handle (no API — Firefox,
Safari, Brave — or a template) is no longer recorded: nothing could
ever reopen it, so every click failed and dropped the entry. A startup
prune clears such stale entries. Reopening now asks for 'read' instead
of 'readwrite' (Save re-prompts on its own), and a declined permission
prompt keeps the entry — only a moved or deleted file drops it.