Adopt `stac-partition-extension` on collections

Type

Task

Scope

Multi-theme or Platform

Skillset

engineering

Description

Context

Consumers currently reconstruct the parquet glob (.../release/<version>/theme=<X>/type=<Y>/*.parquet) from documentation before they can query with DuckDB, PyArrow, or GDAL. The stac-partition-extension puts that glob and its layout on the Collection itself so tools discover it directly. Overture's per-(theme, type) collection layout was the extension's motivating example.

Proposed change

In theme.rs:

• Add the partition extension schema to the collection's stac_extensions.
• Set partition:scheme = "hive", partition:glob = "https://overturemaps-us-west-2.s3.us-west-2.amazonaws.com/release/<release>/theme=<theme>/type=<type>/*.parquet", and partition:file_count = <fragment count> (already known — same value used for the collection's item links).
• Fill partition:keys from the theme/type Hive prefix (theme, type, both string). Confirm this matches the extension's intent — Overture's collections are per-(theme, type), so the keys are technically resolved at the collection level; leaving partition:keys = [] may be more accurate but the field is required by the spec (worth raising upstream if empty isn't valid).