Update dataset card with additional metadata

Add scz2013sweden (9,898,078 rows)

Add scz2018clozuk (8,064,799 rows)

Add scz2011 (1,366,675 rows)

Update configs with all uploaded datasets

Fix configs: only include uploaded datasets, set valid default

Fix YAML indentation for dataset viewer

Add default config for dataset viewer

Add PGC Schizophrenia GWAS summary statistics (parquet, 10k-row shards)

initial commit