fix: increase network timeout and batch size for GP lookup queries (Task 3.2)

Dry run test revealed GP lookup queries timing out at 30s (connection_timeout
in snowflake.toml). Increased to 600s. Also increased batch_size from 500 to
5000 — query time is ~40s regardless of batch size (CTE compilation overhead),
so larger batches reduce total time from ~50min to ~6min for 36K patients.

Dry run results: 91.8% GP match rate, 49.3% drug-indication match rate,
42,072 modified UPIDs, 1,846 pathway nodes across 6 date filters.

cli/refresh_pathways.py

@@ -407,7 +407,7 @@ def refresh_pathways(
                     gp_matches_df = get_patient_indication_groups(
                         patient_pseudonyms=patient_pseudonyms,
                         connector=connector,
-                        batch_size=500,
+                        batch_size=5000,
                         earliest_hcd_date=earliest_hcd_date_str,
                     )