fix(simulation): address PR #50 review — determinism, overflow, invariants

- Sort eligible NPCs by StableId for deterministic conversation pairing (D-010)
- Replace single_mut() with per-observer iteration (D-010 principle 3, D-027)
- Widen current_stress * 100 to i32 in mood derivation to prevent i16 overflow
- Promote line_interval to named constant LINE_INTERVAL_TICKS
- Add 4 Sprint 14 component invariants (MoodState, InteractionMemory,
  ActivityState+PathRequest exclusion, double-tagged tier detection)
- Attach MoodState to content spawn pipeline and gauntlet fixup
- VecDeque for InteractionMemory.notable_events (O(1) pop_front)
- Rename who_knows() to who_knows_full_scan() to communicate O(N) cost
- Add O(N^2) growth limit comment on conversation pair scan
- Document Suspicious/Focused as externally-set moods on enum variants

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

server/src/test_world/mod.rs

@@ -495,6 +495,48 @@ pub fn setup_gauntlet(app: &mut App) {
     }
 
     app.insert_resource(snapshots);
+
+    // --- Sprint 14 component fixup ---
+    // Attach MoodState and InteractionMemory to all Npc entities that are
+    // missing them. Gauntlet room builders don't include these yet — this
+    // ensures invariant S14-1/S14-2 pass and the mood/trust systems have
+    // valid component targets.
+    {
+        use crate::npc::interaction::InteractionMemory;
+        use crate::npc::mood::MoodState;
+        use crate::npc::Npc;
+
+        let missing_mood: Vec<bevy_ecs::prelude::Entity> = {
+            let mut q = app
+                .world_mut()
+                .query_filtered::<bevy_ecs::prelude::Entity, (
+                    bevy_ecs::prelude::With<Npc>,
+                    bevy_ecs::prelude::Without<MoodState>,
+                )>();
+            q.iter(app.world()).collect()
+        };
+        for entity in missing_mood {
+            app.world_mut()
+                .entity_mut(entity)
+                .insert(MoodState::default());
+        }
+
+        let missing_mem: Vec<bevy_ecs::prelude::Entity> = {
+            let mut q = app
+                .world_mut()
+                .query_filtered::<bevy_ecs::prelude::Entity, (
+                    bevy_ecs::prelude::With<Npc>,
+                    bevy_ecs::prelude::Without<InteractionMemory>,
+                )>();
+            q.iter(app.world()).collect()
+        };
+        for entity in missing_mem {
+            app.world_mut()
+                .entity_mut(entity)
+                .insert(InteractionMemory::default());
+        }
+    }
+
     app.insert_resource(registry);
 }