Place similarity

Derived-similarity layer. Circle a place and ask the map to find similar ones. Answers the similarity verb only (BigQuery VECTOR_SEARCH over a precomputed coarse table); paints nothing until a query runs. Cost-gated OFF by default (EMBEDDINGS_ENABLED) with a maximumBytesBilled ceiling; degrades to 'not available yet' until the offline coarse-cell build runs. Attribution: The AlphaEarth Foundations Satellite Embedding dataset is produced by Google and Google DeepMind.