ORT platform npm packages

Chose generated @loreai/onnxruntime-<target> optional packages over relying on onnxruntime-node postinstall because npm 12, offline, proxied, and air-gapped installs cannot reliably download GitHub-release binaries. Packages contain the addon and sibling libraries, use npm os/cpu gates and preferUnplugged, have no install script or exports map, and are version-pinned into the gateway tarball. Unsupported or absent targets fall back to bundled WASM.