Replace the in-memory loadConfig() stub with real ~/.core/gui/config.yaml
loading via go-config. handleConfigTask now persists changes to disk via
cfg.Set() + cfg.Commit(). Sub-service applyConfig() stubs fleshed out:
window reads default dimensions (TODO: Manager API), systray stores icon
path, menu reads show_dev_tools flag with accessor.
Co-Authored-By: Virgil <virgil@lethean.io>
Window package is now a full core.Service with typed IPC messages.
Register(Platform) factory closure captures platform adapter for WithService.
OnStartup queries config and registers query/task handlers.
Platform events converted to IPC actions via trackWindow.
Co-Authored-By: Virgil <virgil@lethean.io>
