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.Core/World/Generation/WorldGenContext.cs

@@ -0,0 +1,37 @@
+using Theriapolis.Core.Data;
+using Theriapolis.Core.Util;
+
+namespace Theriapolis.Core.World.Generation;
+
+/// <summary>
+/// Accumulating context passed through the world-generation pipeline.
+/// Holds the WorldState under construction, per-subsystem RNG streams, and a logger.
+/// </summary>
+public sealed class WorldGenContext
+{
+    public WorldState World { get; }
+
+    /// <summary>Named RNG sub-streams, keyed by the subsystem constant name.</summary>
+    public Dictionary<string, SeededRng> Rngs { get; } = new();
+
+    /// <summary>Directory that holds macro_template.json, biomes.json, etc.</summary>
+    public string DataDirectory { get; init; } = "";
+
+    /// <summary>Called after each stage completes: (stageName, progressFraction 0–1).</summary>
+    public Action<string, float>? ProgressCallback { get; set; }
+
+    /// <summary>Simple diagnostic log sink.</summary>
+    public Action<string>? Log { get; set; }
+
+    public WorldGenContext(ulong seed, string dataDirectory)
+    {
+        World = new WorldState { WorldSeed = seed };
+        DataDirectory = dataDirectory;
+    }
+
+    public void ReportProgress(string stageName, float fraction)
+        => ProgressCallback?.Invoke(stageName, Math.Clamp(fraction, 0f, 1f));
+
+    public void LogMessage(string msg)
+        => Log?.Invoke(msg);
+}