generate thumbnails

backend/internal/db/migrations/011_thumbnails.down.sql

@@ -0,0 +1 @@
+DROP TABLE IF EXISTS thumbnails;

backend/internal/db/migrations/011_thumbnails.up.sql

@@ -0,0 +1,14 @@
+CREATE TABLE thumbnails (
+    id               TEXT PRIMARY KEY DEFAULT gen_random_uuid(),
+    file_id          TEXT NOT NULL REFERENCES files(id) ON DELETE CASCADE,
+    page_number      INTEGER NOT NULL,
+    resolution_label TEXT NOT NULL,
+    width            INTEGER NOT NULL,
+    height           INTEGER NOT NULL,
+    storage_key      TEXT NOT NULL,
+    mime_type        TEXT NOT NULL DEFAULT 'image/jpeg',
+    created_at       TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE INDEX idx_thumbnails_file_id ON thumbnails(file_id);
+CREATE UNIQUE INDEX idx_thumbnails_unique ON thumbnails(file_id, page_number, resolution_label);