feat: add minValues and maxValues support to StatisticsCollector

- Add min/max tracking for all supported types
- Primitive types (int8-64, uint8-64, float32/64)
- Date, timestamp with all time units
- Decimal128
- String types with truncation to 32 chars
- Merge min/max across multiple batches
- Tests for min/max across single and multiple batches

Author: DrakeLin