feat(data): add spatial extension + extraction API keys

- Add GEONAMES_USERNAME=padelnomics and CENSUS_API_KEY to .env.dev.sops and .env.prod.sops
- Enable DuckDB spatial extension in SQLMesh config.yaml (ST_Distance_Sphere for distance calcs + future map features)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

transform/sqlmesh_padelnomics/config.yaml

@@ -4,6 +4,8 @@ gateways:
       type: duckdb
       catalogs:
         local: "{{ env_var('DUCKDB_PATH', 'data/lakehouse.duckdb') }}"
+      extensions:
+        - spatial
 
 default_gateway: duckdb