P3-01: Plugin system (dylib-based)

[hybridmachine]

Description

Dynamic plugin loading system for extending the editor.

Implementation

• dlopen/dlsym based plugin loading from ~/Library/Application Support/MacNote++/plugins/
• C interface similar to Windows N++ plugin API
• Required exports: setInfo, getName, getFuncsArray, beNotified, messageProc
• Plugin menu integration (Plugins menu populated from loaded plugins)
• Plugin Admin panel for enable/disable
• Plugin API documentation
• Sample plugin project

Key Files

• macos/platform/main_phase7.mm (or new plugin_manager files)