fix(embeddings): scope the memory client's default embedder to config credentials - #5515

The change adds explicit embedding_endpoint and embedding_model values to a test setup so the effective-embedder ladder resolves to a local Ollama route without requiring an installed host. The added settings are consistent with the existing ollama:all-minilm:latest provider string, and the comment makes the intent clear. I cannot see get_settings or the memory_tree struct definition from here, so I cannot verify the field names or that resolution does not probe the endpoint — but a missing field or a wrong field name would fail to compile, and the change otherwise looks sound. No findings. The code index for this repository is cold, so this review saw the diff alone.

No findings.