Ports the CLI to the library API. collections/files/get/get-thumb use the fresh read variants (Library.fresh(), current server state); backup runs lib.backup; backup-metadata and the missing-thumbnail helpers enumerate via the library. files/get output is byte-identical to the pre-port CLI — raw metadata.title, microsecond creationTime, pre-port row order — exit codes unchanged. Adds --cache-dir; fixes the helper JPEG-only assumption (closes#17).
Model: opus-4-8
