feat(simulation): knowledge grant schema, events, and contradiction detection (#545, #546, #547)

KnowledgeGrant untagged enum (Fact + Entity variants), ContentEntityRegistry
resource, KnowledgeGranted event processing, ContradictionClaim struct with
600-tick window detection in observe_entity. Wires knowledge_grant field in
dialogue line selection. Implements D-079, D-083. Closes Q-026.

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

server/src/content/mod.rs

@@ -20,6 +20,8 @@ use bevy_app::prelude::*;
 use bevy_ecs::prelude::*;
 use std::path::PathBuf;
 
+use crate::knowledge::ContentEntityRegistry;
+
 /// Configuration for the content loader.
 /// Set the content root path before adding ContentPlugin.
 #[derive(Resource, Debug, Clone)]
@@ -52,6 +54,10 @@ impl Plugin for ContentPlugin {
             app.insert_resource(ContentConfig::default());
         }
 
+        // ContentEntityRegistry is required by spawn_npc (D-079).
+        // Init here so ContentPlugin works standalone without KnowledgePlugin.
+        app.init_resource::<ContentEntityRegistry>();
+
         app.add_systems(Startup, load_and_spawn_content);
         app.add_systems(PostUpdate, hot_reload::hot_reload_content);