refactor(simulation): apply rustfmt formatting

Formatting-only changes across server source and test files.
No logic changes.

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

server/src/content/hot_reload.rs

@@ -87,7 +87,11 @@ const MAX_WALK_DEPTH: usize = 100;
 /// Stops recursing at MAX_WALK_DEPTH to guard against symlink loops.
 fn walk_yaml(dir: &Path, timestamps: &mut BTreeMap<PathBuf, SystemTime>, depth: usize) {
     if depth >= MAX_WALK_DEPTH {
-        tracing::warn!("walk_yaml: max depth {} reached at {:?}, stopping", MAX_WALK_DEPTH, dir);
+        tracing::warn!(
+            "walk_yaml: max depth {} reached at {:?}, stopping",
+            MAX_WALK_DEPTH,
+            dir
+        );
         return;
     }
     let Ok(entries) = std::fs::read_dir(dir) else {

server/src/content/spawn.rs

@@ -197,9 +197,10 @@ fn spawn_npc(world: &mut World, profile: &types::NpcProfile, result: &mut SpawnR
 
     // Register in EntityRegistry for StableId mapping
     let stable_id = world.resource_mut::<EntityRegistry>().register(entity);
-    world
-        .entity_mut(entity)
-        .insert((StableEntityId(stable_id), ContentSlug(profile.canonical_id.clone())));
+    world.entity_mut(entity).insert((
+        StableEntityId(stable_id),
+        ContentSlug(profile.canonical_id.clone()),
+    ));
 
     result
         .npc_ids