feat(app): wire plugin host, ship smoke plugin, log lifecycle

Phase 1 MVP end-to-end. Program.cs initializes Serilog, builds an
AppPluginHost that hands plugins a SerilogAdapter (IPluginLogger),
discovers plugins from the App's output plugins/ dir, loads each via
PluginLoader, calls Enable on all of them before opening the GameWindow,
and calls Disable in a finally block on shutdown.

AcDream.Plugins.Smoke is a new first-party plugin that logs through
the host during Initialize / Enable / Disable. Its csproj references
the abstractions with Private=false + ExcludeAssets=runtime to avoid
shipping a second copy of AcDream.Plugin.Abstractions.dll (which would
break ALC type identity). An MSBuild Target on the App project copies
the plugin DLL into plugins/AcDream.Plugins.Smoke/ and writes the
plugin.json manifest next to it.

Smoke verified against real dats. Console output observed:
  [INF] scanning plugins in ...\plugins
  [INF] smoke plugin initialized
  [INF] loaded plugin acdream.smoke (Smoke Plugin)
  [INF] smoke plugin enabled
  loaded landblock 0xA9B4FFFF
  <window renders terrain>
  [INF] smoke plugin disabled  (on shutdown)

Phase 1 done.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

AcDream.slnx

@@ -4,6 +4,7 @@
     <Project Path="src/AcDream.Cli/AcDream.Cli.csproj" />
     <Project Path="src/AcDream.Core/AcDream.Core.csproj" />
     <Project Path="src/AcDream.Plugin.Abstractions/AcDream.Plugin.Abstractions.csproj" />
+    <Project Path="src/AcDream.Plugins.Smoke/AcDream.Plugins.Smoke.csproj" />
   </Folder>
   <Folder Name="/tests/">
     <Project Path="tests/AcDream.Core.Tests.Fixtures.HelloPlugin/AcDream.Core.Tests.Fixtures.HelloPlugin.csproj" />

src/AcDream.App/AcDream.App.csproj

@@ -24,4 +24,26 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
   </ItemGroup>
+  <ItemGroup>
+    <!-- Build the smoke plugin first and copy it into plugins/AcDream.Plugins.Smoke/ -->
+    <ProjectReference Include="..\AcDream.Plugins.Smoke\AcDream.Plugins.Smoke.csproj">
+      <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
+      <SkipGetTargetFrameworkProperties>true</SkipGetTargetFrameworkProperties>
+    </ProjectReference>
+  </ItemGroup>
+  <Target Name="CopySmokePluginToPluginsDir" AfterTargets="Build">
+    <PropertyGroup>
+      <_SmokePluginSourceDir>..\AcDream.Plugins.Smoke\bin\$(Configuration)\net10.0</_SmokePluginSourceDir>
+      <_SmokePluginDestDir>$(OutputPath)plugins\AcDream.Plugins.Smoke</_SmokePluginDestDir>
+    </PropertyGroup>
+    <MakeDir Directories="$(_SmokePluginDestDir)" />
+    <Copy
+      SourceFiles="$(_SmokePluginSourceDir)\AcDream.Plugins.Smoke.dll"
+      DestinationFolder="$(_SmokePluginDestDir)"
+      SkipUnchangedFiles="true" />
+    <WriteLinesToFile
+      File="$(_SmokePluginDestDir)\plugin.json"
+      Overwrite="true"
+      Lines="{ &quot;id&quot;: &quot;acdream.smoke&quot;, &quot;displayName&quot;: &quot;Smoke Plugin&quot;, &quot;version&quot;: &quot;0.1.0&quot;, &quot;entryDll&quot;: &quot;AcDream.Plugins.Smoke.dll&quot;, &quot;apiVersion&quot;: 1 }" />
+  </Target>
 </Project>

src/AcDream.App/Plugins/AppPluginHost.cs

@@ -0,0 +1,9 @@
+using AcDream.Plugin.Abstractions;
+
+namespace AcDream.App.Plugins;
+
+public sealed class AppPluginHost : IPluginHost
+{
+    public AppPluginHost(IPluginLogger log) => Log = log;
+    public IPluginLogger Log { get; }
+}

src/AcDream.App/Plugins/SerilogAdapter.cs

@@ -0,0 +1,12 @@
+using AcDream.Plugin.Abstractions;
+
+namespace AcDream.App.Plugins;
+
+public sealed class SerilogAdapter : IPluginLogger
+{
+    private readonly Serilog.ILogger _log;
+    public SerilogAdapter(Serilog.ILogger log) => _log = log;
+    public void Info(string message) => _log.Information("{Message}", message);
+    public void Warn(string message) => _log.Warning("{Message}", message);
+    public void Error(string message, Exception? exception = null) => _log.Error(exception, "{Message}", message);
+}

src/AcDream.App/Program.cs

@@ -1,15 +1,61 @@
+using AcDream.App.Plugins;
 using AcDream.App.Rendering;
+using AcDream.Core.Plugins;
+using Serilog;
 
-var datDir = args.FirstOrDefault()
-             ?? Environment.GetEnvironmentVariable("ACDREAM_DAT_DIR");
+Log.Logger = new LoggerConfiguration()
+    .MinimumLevel.Debug()
+    .WriteTo.Console()
+    .CreateLogger();
 
+var datDir = args.FirstOrDefault() ?? Environment.GetEnvironmentVariable("ACDREAM_DAT_DIR");
 if (string.IsNullOrWhiteSpace(datDir))
 {
-    Console.Error.WriteLine("usage: AcDream.App <dat-directory>");
-    Console.Error.WriteLine("   or: set ACDREAM_DAT_DIR and run with no args");
+    Log.Error("usage: AcDream.App <dat-directory>  (or set ACDREAM_DAT_DIR)");
     return 2;
 }
 
-using var window = new GameWindow(datDir);
-window.Run();
+var host = new AppPluginHost(new SerilogAdapter(Log.Logger));
+
+var pluginsDir = Path.Combine(AppContext.BaseDirectory, "plugins");
+Log.Information("scanning plugins in {PluginsDir}", pluginsDir);
+
+var loaded = new List<LoadedPlugin>();
+foreach (var result in PluginDiscovery.Scan(pluginsDir))
+{
+    if (!result.Success)
+    {
+        Log.Warning("plugin discovery failed for {Dir}: {Error}", result.PluginDirectory, result.Error);
+        continue;
+    }
+
+    var loadResult = PluginLoader.Load(result.PluginDirectory, result.Manifest!, host);
+    if (!loadResult.Success)
+    {
+        Log.Warning("plugin load failed for {Id}: {Error}", result.Manifest!.Id, loadResult.Error);
+        continue;
+    }
+
+    loaded.Add(loadResult);
+    Log.Information("loaded plugin {Id} ({DisplayName})", result.Manifest!.Id, result.Manifest.DisplayName);
+}
+
+foreach (var plugin in loaded)
+    plugin.Plugin!.Enable();
+
+try
+{
+    using var window = new GameWindow(datDir);
+    window.Run();
+}
+finally
+{
+    foreach (var plugin in loaded)
+    {
+        try { plugin.Plugin!.Disable(); }
+        catch (Exception ex) { Log.Error(ex, "plugin disable failed: {Id}", plugin.Manifest.Id); }
+    }
+    Log.CloseAndFlush();
+}
+
 return 0;

src/AcDream.Plugins.Smoke/AcDream.Plugins.Smoke.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <LangVersion>latest</LangVersion>
+    <!-- Plugin DLLs are copied to plugins/<id>/ at build of AcDream.App.
+         They must NOT bring AcDream.Plugin.Abstractions.dll with them;
+         the host already owns it. -->
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\AcDream.Plugin.Abstractions\AcDream.Plugin.Abstractions.csproj">
+      <Private>false</Private>
+      <ExcludeAssets>runtime</ExcludeAssets>
+    </ProjectReference>
+  </ItemGroup>
+</Project>

src/AcDream.Plugins.Smoke/SmokePlugin.cs

@@ -0,0 +1,17 @@
+using AcDream.Plugin.Abstractions;
+
+namespace AcDream.Plugins.Smoke;
+
+public sealed class SmokePlugin : IAcDreamPlugin
+{
+    private IPluginHost? _host;
+
+    public void Initialize(IPluginHost host)
+    {
+        _host = host;
+        _host.Log.Info("smoke plugin initialized");
+    }
+
+    public void Enable() => _host?.Log.Info("smoke plugin enabled");
+    public void Disable() => _host?.Log.Info("smoke plugin disabled");
+}