client/v2.6.2

# Release Notes - Milvus Go SDK v2.6.2

## Summary

  This release introduces QueryIterator support for efficient large result set iteration and adds Struct Array field type support in the Go SDK.

## New Features

### QueryIterator Support

  Added QueryIterator for efficiently iterating over large query result sets using PK-based pagination (#46633).

  - Support for Int64 and VarChar primary key types for automatic pagination
  - Configurable options via QueryIteratorOption:
    - WithBatchSize(int) - Set batch size for each iteration (default: 1000)
    - WithIteratorLimit(int64) - Set overall limit of entries to iterate
    - WithFilter(string) - Set filter expression
    - WithOutputFields(...string) - Specify output fields
    - WithPartitions(...string) - Specify partition names
    - WithConsistencyLevel(ConsistencyLevel) - Set consistency level

  Usage Example:
```
  opt := milvusclient.NewQueryIteratorOption("collection_name").
      WithBatchSize(500).
      WithFilter("age > 18").
      WithOutputFields("id", "name", "vector")

  iter, err := client.QueryIterator(ctx, opt)
  for {
      rs, err := iter.Next(ctx)
      if errors.Is(err, io.EOF) {
          break
      }
      // process rs...
  }
```

## Enhancements

###  Struct Array Field Type Support (#45291)

  Added support for Struct Array field type in Go SDK:

  - New columnStructArray type implementing the Column interface
  - Support for parsing StructArrayField from protobuf responses
  - Schema construction support for struct array fields via entity.FieldTypeArray

  Test Infrastructure Improvements (#45113)

  - Refactored go_client test wrapper to use struct embedding pattern
  - Improved test structure and organization

##  Related PRs

  - #45113 - Refactor go_client test wrapper
  - #45291 - Support struct array field type
  - #46633 - Add QueryIterator support