-- Adds two nullable metadata columns populated by ThumbnailService when it
-- generates the JPEG preview: thumbnail_aspect (PORTRAIT | LANDSCAPE, from the
-- source image w/h ratio with threshold 1.1) and page_count (from PDDocument
-- for PDFs, 1 for image uploads). Both are null until the existing admin
-- backfill endpoint (/api/admin/generate-thumbnails) reruns the service.
ALTER TABLE documents
    ADD COLUMN thumbnail_aspect VARCHAR(16),
    ADD COLUMN page_count INTEGER;
