fix(simulation): address PR #125 review — tick truncation, ordering, perf, protocol test

- Widen EventPort tick methods from u32 to u64 (prevents overflow)
- Add is_identity() guard on hot-path String allocation in modifiers
- Replace Vec::remove(0) with VecDeque::pop_front() in price history
- Add .after(tick_economy_simulation) ordering for debug commands
- Fix stale PROTOCOL_VERSION assertion (20 → 21) in serialization test
- Add D-181 Phase 2 visibility scope comment on serve_econ_state_query
- Eliminate double lookup in rebuild_signals via single-pass extraction
- Track economy seed TODO with backlog ticket reference

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

tooling/econ-sim/src/events.rs

@@ -130,7 +130,7 @@ struct ActiveEvent {
 
 struct ScheduledEvent {
     /// The simulation tick at which to activate this event.
-    inject_at_tick: u32,
+    inject_at_tick: u64,
     event: EconEvent,
 }
 
@@ -165,7 +165,7 @@ impl EventPort {
     ///
     /// The event becomes active at the START of `inject_at_tick`, before
     /// `compute_modifiers` is called for that tick.
-    pub fn push_at(&mut self, inject_at_tick: u32, event: EconEvent) {
+    pub fn push_at(&mut self, inject_at_tick: u64, event: EconEvent) {
         self.scheduled.push(ScheduledEvent {
             inject_at_tick,
             event,
@@ -175,7 +175,7 @@ impl EventPort {
     /// Activate any events scheduled for `current_tick`.
     ///
     /// Call at the START of each tick, before `compute_modifiers`.
-    pub fn activate_scheduled(&mut self, current_tick: u32) {
+    pub fn activate_scheduled(&mut self, current_tick: u64) {
         // Stable Rust: partition scheduled list manually (no drain_filter).
         let mut still_pending = Vec::new();
         let mut to_activate = Vec::new();
@@ -289,7 +289,11 @@ pub struct EventModifiers {
 impl EventModifiers {
     /// Combined demand multiplier for `(system_id, commodity_id)`.
     /// Returns `1.0` if no active demand shock targets this pair.
+    /// Guards String allocation: fast-path returns 1.0 when no demand events are active.
     pub fn demand_for(&self, system_id: &str, commodity_id: &str) -> f64 {
+        if self.demand.is_empty() {
+            return 1.0;
+        }
         *self
             .demand
             .get(&(system_id.to_string(), commodity_id.to_string()))
@@ -297,7 +301,11 @@ impl EventModifiers {
     }
 
     /// Combined productivity multiplier for `(system_id, commodity_id)`.
+    /// Guards String allocation: fast-path returns 1.0 when no productivity events are active.
     pub fn productivity_for(&self, system_id: &str, commodity_id: &str) -> f64 {
+        if self.productivity.is_empty() {
+            return 1.0;
+        }
         *self
             .productivity
             .get(&(system_id.to_string(), commodity_id.to_string()))
@@ -305,7 +313,11 @@ impl EventModifiers {
     }
 
     /// Combined capacity multiplier for `(system_id, commodity_id)`.
+    /// Guards String allocation: fast-path returns 1.0 when no capacity events are active.
     pub fn capacity_for(&self, system_id: &str, commodity_id: &str) -> f64 {
+        if self.capacity.is_empty() {
+            return 1.0;
+        }
         *self
             .capacity
             .get(&(system_id.to_string(), commodity_id.to_string()))

tooling/econ-sim/src/main.rs

@@ -376,7 +376,7 @@ fn run_shock_response_test(
     // Schedule: inject 90% capacity disruption at tick WARMUP_TICKS
     let mut port = events::EventPort::new();
     port.push_at(
-        WARMUP_TICKS,
+        WARMUP_TICKS as u64,
         events::EconEvent {
             target: events::EconEventTarget::Node(shock_node.clone()),
             effect: events::EconEventEffect::CapacityMultiplier(0.1),

tooling/econ-sim/src/model.rs

@@ -135,7 +135,7 @@ pub fn run_with_events(
 
     for tick in 0..ticks {
         // Activate any events scheduled for this tick (D-180)
-        events.activate_scheduled(tick);
+        events.activate_scheduled(tick as u64);
 
         let mods = events.compute_modifiers(economy);
         step_inner(economy, productivity, shadow, &archetypes, &mut nodes, &mods, ALPHA);

tooling/econ-sim/src/sim.rs

@@ -103,8 +103,7 @@ impl Simulation {
     /// event port. Call once per economy tick (every ECON_TICK_RATE game ticks).
     pub fn step(&mut self) {
         // Activate any events scheduled for this tick (D-180)
-        let tick32 = self.tick as u32;
-        self.events.activate_scheduled(tick32);
+        self.events.activate_scheduled(self.tick);
 
         let mods = self.events.compute_modifiers(&self.economy);