feat(simulation): composable behavior engine — action+modifier+context primitives (#633)

Replaces flat culture×zone×role behavior strings with three-layer
composition: BehaviorAction (role-generic), BehaviorModifier (culture
coloring), BehaviorContext (situation gating). Assembly at NpcBlueprint
instantiation. Backward compatible — falls back to legacy behaviors
when primitives are empty. D-139 filed, Q-057 resolved.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/npc/mod.rs

@@ -117,6 +117,16 @@ impl Plugin for NpcPlugin {
 #[derive(Component, Debug)]
 pub struct Npc;
 
+/// Voice culture identifier for an NPC entity (D-138).
+///
+/// Stores the culture_id used to key the voice cache. Attached at spawn time
+/// by the content system or generator. Absent NPCs fall back to base text.
+#[derive(Component, Debug, Clone)]
+pub struct NpcVoiceProfile {
+    pub culture_id: String,
+}
+
+
 /// NPC animation tier (D-047).
 ///
 /// Tier 1 (clear): public daily activities — instantly readable.