Initial commit: Theriapolis baseline at port/godot branch point

Captures the pre-Godot-port state of the codebase. This is the rollback
anchor for the Godot port (M0 of theriapolis-rpg-implementation-plan-godot-port.md).
All Phase 0 through Phase 6.5 work is included; Phase 7 is in flight.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Theriapolis.Desktop/Program.cs

@@ -0,0 +1,37 @@
+using Theriapolis.Game;
+
+// Resolve content directories relative to the executable.
+//   Distribution: Data/ and Gfx/ sit next to the exe (absolute path)
+//   Development:  walk up from the exe to find Content/Data and Content/Gfx
+string dataDir = ResolveContentDir("Data");
+string gfxDir  = ResolveContentDir("Gfx");
+
+static string ResolveContentDir(string subdir)
+{
+    // 1. "<subdir>" next to the executable — distribution layout
+    string local = Path.Combine(AppContext.BaseDirectory, subdir);
+    if (Directory.Exists(local)) return local;
+
+    // 2. Walk up from the exe to find Content/<subdir> — development layout.
+    //    Trim the trailing separator first: on Windows AppContext.BaseDirectory ends
+    //    with '\', and GetDirectoryName on a trailing-slash path strips the slash
+    //    without ascending, wasting one iteration.
+    string? dir = AppContext.BaseDirectory.TrimEnd(
+        Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
+    for (int i = 0; i < 6; i++)
+    {
+        if (dir is null) break;
+        string candidate = Path.Combine(dir, "Content", subdir);
+        if (Directory.Exists(candidate)) return candidate;
+        dir = Path.GetDirectoryName(dir);
+    }
+
+    return local; // missing-file errors will surface from the consumer with the bad path
+}
+
+using var game = new Game1
+{
+    ContentDataDirectory = dataDir,
+    ContentGfxDirectory  = gfxDir,
+};
+game.Run();

Theriapolis.Desktop/Theriapolis.Desktop.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <RootNamespace>Theriapolis.Desktop</RootNamespace>
+    <AssemblyName>Theriapolis.Desktop</AssemblyName>
+    <LangVersion>12</LangVersion>
+    <!-- Required for MonoGame DesktopGL native libs to copy correctly -->
+    <RuntimeIdentifiers>win-x64;linux-x64;osx-x64;osx-arm64</RuntimeIdentifiers>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="MonoGame.Framework.DesktopGL" Version="3.8.2.1105" />
+    <!-- MonoGame.Content.Builder.Task is added here when content assets are ready (Phase 2+).
+         Phase 0/1 generates all textures at runtime; no content pipeline pass needed. -->
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\Theriapolis.Game\Theriapolis.Game.csproj" />
+  </ItemGroup>
+  <!-- Copy content data + gfx assets to output alongside the executable -->
+  <ItemGroup>
+    <Content Include="..\Content\Data\**\*"
+             Link="Data\%(RecursiveDir)%(Filename)%(Extension)"
+             CopyToOutputDirectory="PreserveNewest" />
+    <Content Include="..\Content\Gfx\**\*"
+             Link="Gfx\%(RecursiveDir)%(Filename)%(Extension)"
+             CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+  <!-- MonoGame content pipeline reference (activate in Phase 2+ when assets exist):
+  <ItemGroup>
+    <MonoGameContentReference Include="..\Content\Content.mgcb" />
+  </ItemGroup>
+  -->
+</Project>