Extend field converters (#1986)

This pull request introduces new converters for handling
channels-first/channels-last metadata in image and mask fields, improves
error handling for array structure issues, and expands the set of
annotation field and converter utilities. The changes also include
updates to the public API and add a new test for converter registration.

**New converters and utilities:**

* Added `ChannelsFirstConverter` for image fields and
`MaskChannelsFirstConverter` for mask fields, enabling metadata-only
conversion between channels-first and channels-last formats without
altering the actual data.
[[1]](diffhunk://#diff-370ffd190b01623b335a827152000636d5445190cd9e296694f2884649e55559R399-R449)
[[2]](diffhunk://#diff-be0e9424e00f51a63ddbe9dc5c7f01046dc343d7c335eee9ab198a031a4eaa7aR466-R514)
* Introduced the `copy_columns_with_shape` utility function to assist
converters that only need to update metadata and not the underlying
data.
* Registered new converters and utilities in the `__init__.py` files and
updated the public API to include them.
[[1]](diffhunk://#diff-000e98833d5fba9d66f82db2422b240bd02e0fde9f86af6f7ffd9a431abd5b01R8-R34)
[[2]](diffhunk://#diff-000e98833d5fba9d66f82db2422b240bd02e0fde9f86af6f7ffd9a431abd5b01R45)
[[3]](diffhunk://#diff-000e98833d5fba9d66f82db2422b240bd02e0fde9f86af6f7ffd9a431abd5b01R70-R106)
[[4]](diffhunk://#diff-000e98833d5fba9d66f82db2422b240bd02e0fde9f86af6f7ffd9a431abd5b01R119)

**Annotation fields and factory functions:**

* Added `ellipse_field` factory function and included `EllipseField` and
`CaptionField` in the annotation fields public API.
[[1]](diffhunk://#diff-bc3a3fc9d428403e8e117f703ffc69efaae506a2db15eea759c548e175698e75R382-R402)
[[2]](diffhunk://#diff-29b9ccd281e40c6b1d4f8b918075d0a3f7ba4c4e7d464d6d6f6fb7f917c80e27R14-R22)
[[3]](diffhunk://#diff-29b9ccd281e40c6b1d4f8b918075d0a3f7ba4c4e7d464d6d6f6fb7f917c80e27R59)
[[4]](diffhunk://#diff-29b9ccd281e40c6b1d4f8b918075d0a3f7ba4c4e7d464d6d6f6fb7f917c80e27R86)

**Error handling improvements:**

* Introduced a new `ArrayStructureError` exception for clearer
diagnostics when numpy arrays have improper object dtype structures
during conversion.
[[1]](diffhunk://#diff-c614e227e84e7aa9a984dd6207cc5f44aec1fc9af2032ecefb72273c64f883e3R1-R33)
[[2]](diffhunk://#diff-e324261812079d99ca2989612441e5df1dd15dabde37fb2e5e8c0c1b639dac0dR21)
[[3]](diffhunk://#diff-e324261812079d99ca2989612441e5df1dd15dabde37fb2e5e8c0c1b639dac0dR158-R182)

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### Checklist
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- [x] I have added tests to cover my changes or documented any manual
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- [ ] I have updated the
[documentation](https://github.com/open-edge-platform/datumaro/tree/develop/docs)
accordingly

---------

Signed-off-by: Albert van Houten <[email protected]>
Co-authored-by: Copilot <[email protected]>

Author: AlbertvanHouten

src/datumaro/experimental/converters/__init__.py

@@ -5,15 +5,33 @@
 from datumaro.experimental.converters.annotation_converters import (
     BBoxCoordinateConverter,
     BBoxDtypeConverter,
+    BBoxFormatConverter,
+    BBoxToPolygonConverter,
+    EllipseCoordinateConverter,
+    EllipseDtypeConverter,
+    EllipseToBBoxConverter,
+    KeypointsCoordinateConverter,
+    KeypointsDtypeConverter,
+    KeypointsToBBoxConverter,
     LabelDtypeConverter,
     LabelIndexConverter,
+    PolygonCoordinateConverter,
     PolygonDtypeConverter,
     PolygonToBBoxConverter,
+    RotatedBBoxCoordinateConverter,
     RotatedBBoxDtypeConverter,
+    RotatedBBoxToBBoxConverter,
     RotatedBBoxToPolygonConverter,
 )
-from datumaro.experimental.converters.base import AttributeRemapperConverter, ConversionError, Converter, list_eval_ref
+from datumaro.experimental.converters.base import (
+    AttributeRemapperConverter,
+    ConversionError,
+    Converter,
+    copy_columns_with_shape,
+    list_eval_ref,
+)
 from datumaro.experimental.converters.image_converters import (
+    ChannelsFirstConverter,
     ImageBytesToImageConverter,
     ImageCallableToImageConverter,
     ImagePathToImageConverter,
@@ -24,6 +42,7 @@
 from datumaro.experimental.converters.mask_converters import (
     InstanceMaskCallableToInstanceMaskConverter,
     MaskCallableToMaskConverter,
+    MaskChannelsFirstConverter,
     PolygonToInstanceMaskConverter,
     PolygonToMaskConverter,
 )
@@ -48,30 +67,43 @@
     "AttributeRemapperConverter",
     "BBoxCoordinateConverter",
     "BBoxDtypeConverter",
+    "BBoxFormatConverter",
+    "BBoxToPolygonConverter",
+    "ChannelsFirstConverter",
     "ConversionError",
     "ConversionPaths",
     # Base
     "Converter",
     # Registry
     "ConverterRegistry",
     "ConverterTransform",
+    "EllipseCoordinateConverter",
+    "EllipseDtypeConverter",
+    "EllipseToBBoxConverter",
     "ImageBytesToImageConverter",
     "ImageCallableToImageConverter",
     "ImagePathToImageConverter",
     "ImageToImageInfo",
     "InstanceMaskCallableToInstanceMaskConverter",
+    "KeypointsCoordinateConverter",
+    "KeypointsDtypeConverter",
+    "KeypointsToBBoxConverter",
     "LabelDtypeConverter",
     # Annotation converters
     "LabelIndexConverter",
     "MaskCallableToMaskConverter",
+    "MaskChannelsFirstConverter",
+    "PolygonCoordinateConverter",
     "PolygonDtypeConverter",
     "PolygonToBBoxConverter",
     "PolygonToInstanceMaskConverter",
     # Mask converters
     "PolygonToMaskConverter",
     # Image converters
     "RedBlueColorConverter",
+    "RotatedBBoxCoordinateConverter",
     "RotatedBBoxDtypeConverter",
+    "RotatedBBoxToBBoxConverter",
     "RotatedBBoxToPolygonConverter",
     "UInt8ToFloat32Converter",
     "_can_lazy_converter_handle_conversion",
@@ -84,6 +116,7 @@
     "_is_converter_lazy",
     "_separate_batch_and_lazy_converters",
     "converter",
+    "copy_columns_with_shape",
     "find_conversion_path",
     "list_eval_ref",
 ]