feat: integrate platform backend and application interfaces

server/migrations/0013_v1_upload_idempotency.sql

@@ -0,0 +1,4 @@
+ALTER TABLE upload_objects ADD COLUMN IF NOT EXISTS idempotency_key TEXT;
+CREATE UNIQUE INDEX IF NOT EXISTS upload_objects_owner_idem_uq
+  ON upload_objects(owner_id, idempotency_key)
+  WHERE idempotency_key IS NOT NULL;