fix(simulation): PR #66 review — dedup vision, spawn components, doc fixes

- vision.rs: deduplicate own-tile entity iteration, add same-tile test
- spawn.rs: add NpcVisionState, NpcMemory, PlayerAwareness to content-
  spawned NPCs (matching generate_npc)
- pressure.rs: update who_knows_full_scan doc to reflect actual call
  frequency, document O(N) acceptability at call site
- types.rs: fix stale protocol version comment (13→14)
- generate.rs: format!() → .to_string() (clippy)
- vision.rs: hardcoded 10 → TICKS_PER_GAME_MINUTE
- relationships.rs: fix comment "15%" → "20%" to match code
- pressure.rs: document total() floor-truncation
- save_state.rs: document NpcMemory exclusion as intentional

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

server/src/npc/vision.rs

@@ -30,7 +30,7 @@ use crate::perception::shadowcast::compute_fov;
 use crate::perception::vision_cone::{apply_vision_cone, Facing, VisionConeConfig};
 use crate::simulation::movement::{PlayerCharacter, TilePosition, WalkabilityMap};
 use crate::simulation::spatial::{NaiveSpatialIndex, SpatialIndex};
-use crate::simulation::time::SimulationTime;
+use crate::simulation::time::{SimulationTime, TICKS_PER_GAME_MINUTE};
 use crate::simulation::tier::ActiveSim;
 
 /// NPC vision range in tiles (matches player forward range from VisionConeConfig).
@@ -140,11 +140,10 @@ pub fn compute_npc_vision(
         let mut new_visible = BTreeSet::new();
         let mut player_vis = false;
 
-        // Query entities within vision range, then filter by FOV tile set
-        let nearby = spatial_index.entities_in_range(npc_pos, NPC_VISION_RANGE as u32);
-        let at_origin = spatial_index.entities_at(npc_pos);
+        // Single-pass query: all entities within vision range including own tile
+        let candidates = spatial_index.entities_within(npc_pos, NPC_VISION_RANGE as u32);
 
-        for entity in nearby.into_iter().chain(at_origin.into_iter()) {
+        for entity in candidates {
             if entity == npc_entity {
                 continue;
             }
@@ -262,7 +261,7 @@ pub fn degrade_npc_inferences(
     time: Res<SimulationTime>,
     mut npc_query: Query<&mut NpcMemory, (With<Npc>, With<ActiveSim>)>,
 ) {
-    if time.tick % 10 != 0 {
+    if time.tick % TICKS_PER_GAME_MINUTE != 0 {
         return;
     }
 
@@ -494,6 +493,38 @@ mod tests {
         );
     }
 
+    #[test]
+    fn npc_sees_non_npc_entity_on_same_tile() {
+        let mut world = setup_world(32, 32);
+        let mut registry = EntityRegistry::new(0);
+        let mut spatial = NaiveSpatialIndex::new();
+
+        // NPC at (16, 16)
+        let npc = world
+            .spawn((Npc, ActiveSim, pos(16, 16), NpcVisionState::default()))
+            .id();
+        registry.register(npc);
+        spatial.update(npc, pos(16, 16));
+
+        // Non-NPC entity on the same tile (e.g. dropped item)
+        let item = world.spawn(pos(16, 16)).id();
+        let item_sid = registry.register(item);
+        spatial.update(item, pos(16, 16));
+
+        world.insert_resource(registry);
+        world.insert_resource(spatial);
+
+        let mut schedule = bevy_ecs::schedule::Schedule::default();
+        schedule.add_systems(compute_npc_vision);
+        schedule.run(&mut world);
+
+        let vision = world.get::<NpcVisionState>(npc).unwrap();
+        assert!(
+            vision.visible_entities.contains(&item_sid),
+            "NPC should see non-NPC entity sharing its tile"
+        );
+    }
+
     #[test]
     fn background_npc_not_processed() {
         let mut world = setup_world(32, 32);