[C++][Python] Bind unresolved Substrait expressions using a supplied schema

[malinjawi]

Describe the enhancement requested

This is follow-up work to GH-33985 / PR #34834 now that Substrait can represent unresolved / partially bound expressions (see substrait-io/substrait#515).

Arrow can currently deserialize bound Substrait ExtendedExpression messages, but it cannot yet consume unresolved expressions that contain:

• Expression.NamedExpression
• Type.Unknown
• unresolved function signatures such as add:unknown_unknown

To support front-end filter / projection workflows, Arrow should be able to deserialize these messages using a supplied Arrow schema, bind unresolved names and types against that schema, and then return normal Arrow compute expressions.

Concretely, this means:

• binding NamedExpression to Arrow FieldRef
• treating Type.Unknown as a bind-time placeholder instead of an executable Arrow type
• allowing schema-aware deserialization of ExtendedExpression
• exposing that path in both C++ and Python APIs

The expected API shape is something like:

• C++: DeserializeExpressions(buf, input_schema, ...)
• Python:
  • pyarrow.substrait.deserialize_expressions(buf, schema=...)
  • pyarrow.substrait.BoundExpressions.from_substrait(..., schema=...)
  • pyarrow.compute.Expression.from_substrait(..., schema=...)

This work depends on the Substrait protocol change in substrait-io/substrait#515.

Component(s)

C++, Python