docs: codify entity systems pattern and record combat extensions

docs/PROJECT_CONTEXT.md

@@ -245,11 +245,15 @@ plugin content, not game architecture.
 - Combat is playable: the player swings an equipped sword (left click) and
   dashes (Shift) with cooldowns; hits land against hostile raiders and wolves
   through a deterministic simulation `ConflictSystem`. Wolves hunt hungry
-  nearby villagers, and the hill tribe raids the village when it is short of
+  nearby villagers and the player, and can wound and even down the player
+  (brief forced recovery). The hill tribe raids the village when it is short of
   food while the village holds plenty — unless the tribe reads the village's
   strength (strong NPCs who can swap to defence) and judges victory unlikely,
-  in which case it plans or aborts. Strong villagers automatically defend
-  during a raid.
+  in which case it plans or aborts. During a raid, strong villagers and guards
+  take a real `defend` duty action and rally at the guard post. Hostiles follow
+  the navigation mesh through a shared `CreatureVisual` root, and enemies are
+  data-driven `EnemyDefinition`s so new types add with a definition plus a
+  visual hook.
 - `Escape` releases captured mouse input.
 
 ### Village simulation