Parquet Variant rejects canonical Arrow UInt8/UInt16/UInt32 typed values

[HuaHuaY]

Describe the bug

The Arrow canonical extension specification for arrow.parquet.variant allows
UInt8, UInt16, and UInt32 as Arrow typed_value storage types, with the
following logical Variant mappings:

Arrow typed_value type	Variant primitive type
UInt8	Int16
UInt16	Int32
UInt32	Int64

However, parquet-variant-compute currently rejects these unsigned Arrow types
when constructing or shredding a VariantArray.

There is also an Arrow/Parquet schema boundary that needs special handling:
Parquet itself supports unsigned integer logical types, but the Parquet Variant
shredding specification does not allow unsigned typed_value columns. Therefore,
canonical unsigned Arrow storage must be lowered to the corresponding signed
Parquet shredded type when writing:

Arrow typed_value	Parquet Variant shredded type
UInt8	INT32 with INTEGER(16, true)
UInt16	plain INT32
UInt32	plain INT64

To Reproduce

use arrow_schema::DataType;
use parquet_variant::Variant;
use parquet_variant_compute::{shred_variant, VariantArray};

let input = VariantArray::from_iter([
    Variant::Int16(0),
    Variant::Int16(i16::from(u8::MAX)),
]);

let shredded = shred_variant(&input, &DataType::UInt8)?;

Expected behavior

VariantArray and shred_variant should accept canonical Arrow UInt8, UInt16, and UInt32 typed_value storage.

Additional context

Arrow's documentation: https://arrow.apache.org/docs/format/CanonicalExtensions.html#primitive-type-mappings