v0.1.0

The first public release. Everything below is what the addon does as extracted
from showcade (bd showcade-8i87); it is not a list of changes against an earlier
public version, because there is none.

• Export the Blender selection to GLB and upload it to a
  showcade asset catalog, so a model authored in Blender
  can be bound to a table device from showcade's object editor.
• A stable identity is kept on the collection, so re-exporting and sending again
  updates the same asset rather than creating a second one — the binding in
  showcade follows the new bytes.
• Uploads deduplicate by content hash: sending bytes the catalog already has
  costs a handshake instead of a transfer.
• Sign-in by device-code flow, so credentials are never typed into Blender.
• The upload runs off the main thread; Blender's UI does not block on the network.
• Standard library only, no third-party Python dependencies, and a test suite
  that runs on a clean clone with nothing installed.
• Blender 4.2+ as a proper extension (not a legacy addon), GPL-3.0-or-later.