forked from 1b-agent/opencadstudio-upstream
A V2 plugin passed the version gate and then failed silently while registering its ribbon, since the ribbon wire types have moved on. The host now loads V3 and newer, so V2 plugins are rejected up front with a version message. The V2 compatibility fixture crate goes too. Fixes #1085 Fixes #987 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>