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/Entities/Ai/PoiGuardBehavior.cs

@@ -0,0 +1,20 @@
+namespace Theriapolis.Core.Entities.Ai;
+
+/// <summary>
+/// Defends a point of interest. Phase 5 M5 ships this as Brigand-equivalent
+/// combat behavior — patrolling around a home position is M6 territory once
+/// out-of-combat tactical movement is implemented (currently NPCs only act
+/// during encounters).
+/// </summary>
+public sealed class PoiGuardBehavior : INpcBehavior
+{
+    private readonly BrigandBehavior _melee = new();
+
+    public void TakeTurn(Rules.Combat.Combatant self, AiContext ctx)
+    {
+        // Same combat logic as Brigand. The "patrol around home" behavior
+        // outside of combat hooks in at M6 — for now PoiGuards stand still
+        // until engaged.
+        _melee.TakeTurn(self, ctx);
+    }
+}