CREATE TABLE files (
  id         TEXT PRIMARY KEY NOT NULL,
  name       TEXT NOT NULL,
  mime_type  TEXT NOT NULL DEFAULT '',
  size       INTEGER NOT NULL DEFAULT 0,
  storage_key TEXT NOT NULL,
  checksum   TEXT NOT NULL DEFAULT '',
  ocr_text   TEXT NOT NULL DEFAULT '',
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);