feat: expose Arrow IPC reader via registerArrow and readArrow #37

Is your feature request related to a problem or challenge?

DataFusion 53.1 supports Arrow IPC files via
SessionContext::read_arrow / register_arrow. Since results already
return to the JVM as Arrow batches over the C Data Interface, being
able to round-trip through Arrow IPC files is a natural fit and the
cheapest format to integrate.

Describe the solution you'd like

• Add an ArrowReadOptions value class (file extension, schema).
• Add proto/arrow_read_options.proto and pass options through the
  proto-over-JNI convention (refactor: pass csv and parquet read options via protobuf #29).
• Expose SessionContext.registerArrow(name, path[, options]) and
  readArrow(path[, options]).
• Cover with tests; can write fixtures with arrow-vector's own IPC
  writer to keep test deps minimal.

Describe alternatives you've considered

CREATE EXTERNAL TABLE … STORED AS ARROW via SQL.

Additional context

In the default DataFusion feature set; no Cargo flag changes required.