feat: per-store config (storeScope=store) + effective-store fee resolution
- gp247.json: storeScope=store, version 2.3
- AdminLivewire: storeScoped()/enableKey() so each store enables + configures
its own fee/free-ship threshold via core ConfigForm store-scope - AppConfig::getInfo(): resolveSetting() reads fee/shipping_free for the effective
store (gp247_plugin_store_id) with GLOBAL fallback, group-qualified - Provider: register admin segment into gp247-config.admin.store_scoped_segments
- readme: per-store behaviour note
Co-Authored-By: Claude Opus 4.8 noreply@anthropic.com