timestamp_ns / timestamptz_ns: filter + pruning #4078

Feature Request / Improvement

The ns types were added in #1632, but you can't filter on them yet and there's some other small misc work.

• Bind predicates on ns columns (TimestampNanoLiteral): Add TimestampNano Literal #3853
• Load ns default values from JSON: Add JSON single-value serialization for timestamp_ns and timestamptz_ns #3855
• Check the metrics evaluators and partition projection (year/month/day/hour/bucket) with ns literals
• Avro timestamp-nanos raises "Unknown logical type"
• downcast-ns-timestamp-to-us-on-write renaming Core: Deprecate 'downcast-ns-timestamp-to-us-on-write' config key #3596
• CLI JSON output breaks on ns defaults
• Testing with a fixture (maybe from iceberg-verification?)