Provisional object memory and unknown labeling workflow

[sbrunomello]

Summary

• Track unknown objects by accumulating provisional embeddings and promoting them to named memory
• Extend YOLO detection to emit novelty events, provisional IDs and similarity scores
• Add API, working-memory layer, UI updates and Prometheus metrics for unknown object handling

Testing

• ./gradlew test

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https://chatgpt.com/codex/tasks/task_e_68a12e4efaf0832d8146cd80f79caa50