[OpenCLIP] Tracker: deliver end-to-end support

[tazarov]

Outcome

End-to-end OpenCLIP support in onnx-purego, from model export artifacts to production-ready Go embedding APIs and test/documentation coverage.

Work Breakdown

• [OpenCLIP] Export model and publish Hugging Face artifacts #64
• [OpenCLIP] Implement embeddings/openclip (text + image encoders) #65
• [OpenCLIP] Add integration and parity tests #66
• [OpenCLIP] Add docs and runnable example #67

Definition of Done

• Pinned OpenCLIP ONNX artifacts published and versioned.
• embeddings/openclip supports text + image embeddings for the pinned model.
• Integration/parity tests are green in CI.
• README + example document the full usage path.

[tazarov]

Strict numerical-equivalence follow-up is now tracked in #76.

covers end-to-end OpenCLIP support. tracks the remaining work to prove strict same-artifact numerical parity against the pinned ONNX bundle and tighten the current OpenCLIP parity tolerance in CI.