Fix ONNX runtime dependency and published archive assets

[dev07060]

Summary

• Replace the abandoned ONNX runtime dependency with flutter_onnxruntime and update the embedding service integration.
• Update iOS/macOS example Pod settings and generated lockfiles for the new runtime.
• Keep the published archive complete by including the bundled ONNX model files for 0.19.1.

Scope notes

• This PR contains only the already-committed runtime/package changes from fix/onnxruntime-dependency-version.
• Local untracked docs, promo drafts, screenshots, and example/lib/onnx_runtime_smoke.dart were left out of the PR because they are not needed for the main merge.

Validation

• git diff --check origin/main...HEAD
• flutter analyze lib test
• flutter test