fix(simulation): Clippy cleanup and CI enforcement (#635)

Fix all Clippy warnings across the server codebase (2411 insertions, 1341
deletions). Raise type-complexity-threshold to 750 and too-many-arguments
to 12 in .clippy.toml for idiomatic Bevy ECS system signatures. The server
now passes `cargo clippy -- --deny warnings` cleanly.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/npc/background.rs

@@ -16,11 +16,11 @@
 
 use bevy_ecs::prelude::*;
 
+use crate::npc::mood::{MoodState, NpcMood};
+use crate::npc::routine::ActivityState;
 use crate::npc::{
     Contentment, DailyRoutine, JobPerformance, Npc, Relationships, ToleranceThreshold,
 };
-use crate::npc::mood::{MoodState, NpcMood};
-use crate::npc::routine::ActivityState;
 use crate::simulation::tier::BackgroundSim;
 use crate::simulation::time::{SimulationTime, TICKS_PER_GAME_MINUTE};
 
@@ -110,7 +110,7 @@ pub fn background_tick(
     >,
 ) {
     // Fire once per game-minute (D-031: 10 ticks/minute)
-    if time.tick % TICKS_PER_GAME_MINUTE != 0 {
+    if !time.tick.is_multiple_of(TICKS_PER_GAME_MINUTE) {
         return;
     }
 
@@ -185,16 +185,16 @@ pub fn background_tick(
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::knowledge::types::StableId;
+    use crate::npc::mood::{MoodState, NpcMood};
+    use crate::npc::routine::ActivityState;
     use crate::npc::{
         Contentment, DailyRoutine, JobPerformance, Npc, Relationship, RelationshipKind,
         Relationships, RoutineEntry, ToleranceThreshold,
     };
-    use crate::npc::mood::{MoodState, NpcMood};
-    use crate::npc::routine::ActivityState;
     use crate::simulation::movement::TilePosition;
     use crate::simulation::tier::{ActiveSim, BackgroundSim};
     use crate::simulation::time::{DayPhase, SimulationTime, TICKS_PER_GAME_MINUTE};
-    use crate::knowledge::types::StableId;
     use bevy_ecs::world::World;
 
     // --- derive_background_mood ---
@@ -311,7 +311,10 @@ mod tests {
                 Npc,
                 BackgroundSim,
                 MoodState::default(),
-                ToleranceThreshold { current_stress: 60, threshold: 50 },
+                ToleranceThreshold {
+                    current_stress: 60,
+                    threshold: 50,
+                },
             ))
             .id();
 
@@ -333,7 +336,10 @@ mod tests {
                 Npc,
                 BackgroundSim,
                 MoodState::default(),
-                ToleranceThreshold { current_stress: 60, threshold: 50 },
+                ToleranceThreshold {
+                    current_stress: 60,
+                    threshold: 50,
+                },
             ))
             .id();
 
@@ -353,7 +359,10 @@ mod tests {
                 Npc,
                 BackgroundSim,
                 MoodState::default(),
-                ToleranceThreshold { current_stress: 60, threshold: 50 },
+                ToleranceThreshold {
+                    current_stress: 60,
+                    threshold: 50,
+                },
             ))
             .id();
 
@@ -379,14 +388,21 @@ mod tests {
                     mood: NpcMood::Warm,
                     changed_tick: 0,
                 },
-                ToleranceThreshold { current_stress: 60, threshold: 50 },
+                ToleranceThreshold {
+                    current_stress: 60,
+                    threshold: 50,
+                },
             ))
             .id();
 
         run_system(&mut world);
 
         let mood = world.get::<MoodState>(npc).unwrap();
-        assert_eq!(mood.mood, NpcMood::Warm, "ActiveSim NPC must not be updated by background_tick");
+        assert_eq!(
+            mood.mood,
+            NpcMood::Warm,
+            "ActiveSim NPC must not be updated by background_tick"
+        );
     }
 
     // --- Mood state machine ---
@@ -401,7 +417,10 @@ mod tests {
                 Npc,
                 BackgroundSim,
                 MoodState::default(),
-                ToleranceThreshold { current_stress: 50, threshold: 50 },
+                ToleranceThreshold {
+                    current_stress: 50,
+                    threshold: 50,
+                },
             ))
             .id();
 
@@ -416,9 +435,7 @@ mod tests {
         world.resource_mut::<SimulationTime>().tick = 0;
 
         // No ToleranceThreshold → defaults (0, 50) → Content (0 < 20)
-        let npc = world
-            .spawn((Npc, BackgroundSim, MoodState::default()))
-            .id();
+        let npc = world.spawn((Npc, BackgroundSim, MoodState::default())).id();
 
         run_system(&mut world);
 
@@ -434,8 +451,14 @@ mod tests {
             .spawn((
                 Npc,
                 BackgroundSim,
-                MoodState { mood: NpcMood::Warm, changed_tick: 0 },
-                ToleranceThreshold { current_stress: 55, threshold: 50 },
+                MoodState {
+                    mood: NpcMood::Warm,
+                    changed_tick: 0,
+                },
+                ToleranceThreshold {
+                    current_stress: 55,
+                    threshold: 50,
+                },
             ))
             .id();
 
@@ -456,7 +479,10 @@ mod tests {
             .spawn((
                 Npc,
                 BackgroundSim,
-                MoodState { mood: NpcMood::Content, changed_tick: 42 },
+                MoodState {
+                    mood: NpcMood::Content,
+                    changed_tick: 42,
+                },
             ))
             .id();
 
@@ -464,7 +490,10 @@ mod tests {
 
         let mood = world.get::<MoodState>(npc).unwrap();
         assert_eq!(mood.mood, NpcMood::Content);
-        assert_eq!(mood.changed_tick, 42, "changed_tick must not update when mood unchanged");
+        assert_eq!(
+            mood.changed_tick, 42,
+            "changed_tick must not update when mood unchanged"
+        );
     }
 
     // --- Schedule state machine ---
@@ -564,7 +593,10 @@ mod tests {
         run_system(&mut world);
 
         let rels = world.get::<Relationships>(npc).unwrap();
-        assert_eq!(rels.entries[0].trust_level, 4, "positive trust decrements by 1");
+        assert_eq!(
+            rels.entries[0].trust_level, 4,
+            "positive trust decrements by 1"
+        );
     }
 
     #[test]
@@ -591,7 +623,10 @@ mod tests {
         run_system(&mut world);
 
         let rels = world.get::<Relationships>(npc).unwrap();
-        assert_eq!(rels.entries[0].trust_level, -3, "negative trust increments by 1");
+        assert_eq!(
+            rels.entries[0].trust_level, -3,
+            "negative trust increments by 1"
+        );
     }
 
     #[test]
@@ -709,7 +744,10 @@ mod tests {
                 Npc,
                 BackgroundSim,
                 MoodState::default(),
-                ToleranceThreshold { current_stress: 5, threshold: 50 },
+                ToleranceThreshold {
+                    current_stress: 5,
+                    threshold: 50,
+                },
             ))
             .id();
 
@@ -718,13 +756,19 @@ mod tests {
                 Npc,
                 BackgroundSim,
                 MoodState::default(),
-                ToleranceThreshold { current_stress: 55, threshold: 50 },
+                ToleranceThreshold {
+                    current_stress: 55,
+                    threshold: 50,
+                },
             ))
             .id();
 
         run_system(&mut world);
 
         assert_eq!(world.get::<MoodState>(calm).unwrap().mood, NpcMood::Content);
-        assert_eq!(world.get::<MoodState>(hostile).unwrap().mood, NpcMood::Hostile);
+        assert_eq!(
+            world.get::<MoodState>(hostile).unwrap().mood,
+            NpcMood::Hostile
+        );
     }
 }