Adds the plugin-facing UI registration surface (Task 9, final D.2b task).
Plugins call host.Ui.AddMarkupPanel(path, binding) from Enable(); calls are
buffered in BufferedUiRegistry before the GL window opens, then drained into
UiHost.Root in GameWindow.OnLoad inside the RetailUi block after the first-
party vitals panel. Faulty plugin markup is isolated (try/catch per panel,
logged + skipped). IPluginHost.Ui added; AppPluginHost wired; StubHost in
Core.Tests updated; BufferedUiRegistryTests confirms drain-once semantics.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adds WorldEntitySnapshot, IGameState, IEvents abstractions; WorldEvents
implements replay-on-subscribe with per-handler exception swallowing;
WorldGameState tracks entities; AppPluginHost exposes all three; stubs
wired in Program.cs to keep build green ahead of Task 9 live wiring.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Addresses code quality review of a7f0732:
- LoadedPlugin now holds the AssemblyLoadContext explicitly so Task 10
can call Unload() for hot reload (Critical)
- LoadedPlugin.Error is Exception? to match PluginDiscoveryResult and
preserve stack traces; synthetic failures build FileNotFoundException
and InvalidOperationException (Important)
- PluginLoader falls back to ReflectionTypeLoadException.Types if
GetTypes() can't fully resolve (Important)
- Hardcoded abstractions assembly name is now a const (Minor)
