PR #2775 merged the MeshCore plugin source files but omitted the
parent CMakeLists.txt changes, the export.h API macro, and all
MeshCore-specific Swagger schema types. Without these the plugins
do not build and the REST API serves Meshtastic types for MeshCore
channels.
Adds:
- CMakeLists.txt parent directories + option definitions
- exports/export.h MODEMMESHCORE_API macro
- MeshcoreDemod/Mod swagger YAML specs + SWG client classes
- SWGChannelSettings/Report/Actions/ModelFactory MeshCore types
- Rename 164 Meshtastic donor references in plugin code