feat: use flechette for Arrow decoding.

[jheer]

This PR switches from the apache-arrow reference JS implementation to instead use @uwdata/flechette for Arrow IPC binary data decoding. Flechette is smaller, faster, and provides better coverage of Arrow data types. It also provides a more correct implementation of row proxy objects (that handles nested types) than prior versions of this loader, simplifying the code in this package. As flechette's decoders are very lightweight, this package now bundles flechette so no additional Arrow imports are needed.

If this loader is passed a pre-parsed table, both flechette and apache-arrow tables are supported. Mapping from tables to row objects is now performed by calling the table toArray method. However, performance with apache-arrow tables will be degraded as that library uses very slow proxy row objects (sometimes over 10x slower than flechette).

This PR also modernizes some of the build process and testing code.

Close #364.

[domoritz]

This is great. It's nice that we now bundle the decoder as well.

We decided not to keep the original row proxy but use the reference implementation's toArray method to convert Arrow Table objects to Vega. I think that's okay (and accept the performance deviation) because in most cases I expect people to use this library to load arrow from a URL as in https://github.com/vega/vega-loader-arrow?tab=readme-ov-file#vega-specifications.

Given the size of this library, would it make sense to bake this functionality directly into Vega? Arrow seems to be become enough of an established standard that we could consider supporting it alongside csv and json in Vega.

[jheer]

Given the size of this library, would it make sense to bake this functionality directly into Vega? Arrow seems to be become enough of an established standard that we could consider supporting it alongside csv and json in Vega.

We should double check the size difference, but I think this makes a lot of sense. I'll go ahead with updating this package for now and we can consider rolling it into Vega proper as a separate task.