Implement prototype: venue-driven simulation core, scenarios, tests, and playable entrance scene

- Godot 4.3 project scaffold with first-person guard, procedural world,
  interaction HUD, access inspection, radio forms, debug overlay, shift review
- Simulation core: ShiftCoordinator, VenueScenario, EventScheduler, NPCController/FSM,
  AccessVerifier, EscalationManager, RadioSystem, IncidentRecorder,
  ReputationEvaluator, CrowdSystem, EventBus
- Three authored scenarios (Hollywood Blvd building, The Joke Shop, TV studio)
- Custom headless test runner (25 tests) replacing editor-dependent GUT,
  plus GitHub Actions CI
- Documentation workflow live: README, PLAN (tech stack), TODO/DONE, MEMORY

src/core/crowd_system.gd

@@ -0,0 +1,53 @@
+class_name CrowdSystem
+extends RefCounted
+## Models crowd mood and public reaction (PLAN.md: Public Crowd Reaction).
+
+const EventBus := preload("res://src/core/event_bus.gd")
+## mood: 0.0 (calm) .. 1.0 (panic). attention: how many people are watching.
+
+signal changed(payload: Dictionary)
+
+var event_bus: EventBus = null
+var mood: float = 0.05
+var attention: float = 0.0
+var crowd_panic := false
+
+func set_event_bus(bus: EventBus) -> void:
+	event_bus = bus
+
+## Apply a crowd event. type: "calm_professionalism", "aggressive_behavior",
+## "visible_weapon", "emergency_responder", "de_escalation".
+func apply_event(event_type: String) -> void:
+	match event_type:
+		"calm_professionalism":
+			attention = maxf(0.0, attention - 0.05)
+			mood = maxf(0.0, mood - 0.02)
+		"de_escalation":
+			mood = maxf(0.0, mood - 0.06)
+			attention = clampf(attention + 0.05, 0.0, 1.0)
+		"aggressive_behavior":
+			attention = clampf(attention + 0.20, 0.0, 1.0)
+			mood = clampf(mood + 0.12, 0.0, 1.0)
+		"visible_weapon":
+			attention = 1.0
+			mood = clampf(mood + 0.35, 0.0, 1.0)
+		"emergency_responder":
+			attention = 1.0
+			mood = clampf(mood + 0.25, 0.0, 1.0)
+		_:
+			pass
+	crowd_panic = mood >= 0.75
+	if event_bus:
+		event_bus.crowd_changed.emit({
+			"mood": mood,
+			"attention": attention,
+			"panic": crowd_panic,
+			"event": event_type,
+		})
+
+func summary() -> Dictionary:
+	return {
+		"mood": mood,
+		"attention": attention,
+		"panic": crowd_panic,
+	}