store: Add OidValue::Int4Range and fix block_range binding

Add `OidValue::Int4Range(Bound<i32>, Bound<i32>)` variant to properly
deserialize PostgreSQL int4range columns (OID 3904). Update `select_cols`
in dsl.rs to bind block_range as `Range<Integer>` instead of using the
Bytes placeholder, resolving the existing TODO.