Integrate Bedrock model catalog metadata

crates/galaxy_bedrock_model_catalog/UPSTREAM.md

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+# Upstream provenance
+
+- Source: https://github.com/amazonbedrockmodels/amazonbedrockmodels.github.io
+- Data directory: https://github.com/amazonbedrockmodels/amazonbedrockmodels.github.io/tree/main/data
+- Snapshot commit: recorded in `data/UPSTREAM_COMMIT`
+- Upstream license declaration: MIT, as stated in the upstream README
+
+The upstream project is an unofficial, community-maintained catalog refreshed
+from AWS Bedrock APIs. Its data is useful for discovery and enrichment, but AWS
+documentation and live account/region responses remain authoritative for model
+availability and access.
+
+The JSON files in `data/` are preserved verbatim from upstream. Refresh them
+with `./script/update_bedrock_model_catalog` rather than editing them manually.