Add campfire smoke placeholder

AGRARIAN_DEVELOPMENT_ROADMAP.md

@@ -590,7 +590,9 @@ Target deliverable: A small group can join a server, spawn into one biome, gathe
 - [x] Add cooking placeholder if needed. Added replicated campfire cooking
   placeholder state, a native cookability check, and progress ratio helpers so
   later recipe UI and food systems have a stable hook.
-- [ ] Add smoke/visual effect placeholder.
+- [x] Add smoke/visual effect placeholder. Added a native campfire smoke
+  particle component placeholder that activates and hides with replicated fire
+  state, leaving final visual assets assignable later.
 - [x] Add replication.
 - [ ] Add persistence.
 - [x] Connect fire to body temperature.

Docs/TechnicalDesignDocument.md

@@ -297,6 +297,11 @@ enabled, `AAgrarianCampfire` advances `CookingProgressSeconds` toward
 `CookingSecondsRequired` on the server and exposes `CanCook` plus a normalized
 progress ratio for future recipe UI, food transformation, and interaction hooks.
 
+Campfire visuals include an assetless `SmokeEffect` particle-system component
+placeholder. It is attached above the fire, starts inactive, and follows the
+same replicated lit-state visual update path as fire light intensity so final
+smoke or ember assets can be assigned later without changing gameplay code.
+
 The first real-weather adapter is `UAgrarianWeatherProviderSubsystem`. It uses
 Open-Meteo forecast requests keyed by tile center latitude/longitude, parses the
 current temperature, daily low/high, precipitation, wind, humidity, cloud cover,

Scripts/verify_fire_smoke_placeholder.py

@@ -0,0 +1,44 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+
+REQUIRED = {
+    ROOT / "Source" / "AgrarianGame" / "AgrarianCampfire.h": [
+        "class UParticleSystemComponent;",
+        "TObjectPtr<UParticleSystemComponent> SmokeEffect;",
+    ],
+    ROOT / "Source" / "AgrarianGame" / "AgrarianCampfire.cpp": [
+        "#include \"Particles/ParticleSystemComponent.h\"",
+        "SmokeEffect = CreateDefaultSubobject<UParticleSystemComponent>(TEXT(\"SmokeEffect\"));",
+        "SmokeEffect->bAutoActivate = false;",
+        "SmokeEffect->SetVisibility(false);",
+        "SmokeEffect->SetVisibility(bLit);",
+        "SmokeEffect->ActivateSystem();",
+        "SmokeEffect->DeactivateSystem();",
+    ],
+    ROOT / "AGRARIAN_DEVELOPMENT_ROADMAP.md": [
+        "- [x] Add smoke/visual effect placeholder.",
+    ],
+    ROOT / "Docs" / "TechnicalDesignDocument.md": [
+        "assetless `SmokeEffect` particle-system component",
+    ],
+}
+
+
+def main():
+    missing = []
+    for path, snippets in REQUIRED.items():
+        text = path.read_text(encoding="utf-8")
+        for snippet in snippets:
+            if snippet not in text:
+                missing.append(f"{path.relative_to(ROOT)} missing {snippet!r}")
+
+    if missing:
+        raise SystemExit("Campfire smoke placeholder verification failed:\n" + "\n".join(missing))
+
+    print("PASS: campfire smoke placeholder is implemented and documented.")
+
+
+if __name__ == "__main__":
+    main()

Source/AgrarianGame/AgrarianCampfire.cpp

@@ -4,6 +4,7 @@
 #include "AgrarianGameCharacter.h"
 #include "AgrarianInventoryComponent.h"
 #include "AgrarianSurvivalComponent.h"
+#include "Particles/ParticleSystemComponent.h"
 #include "Components/PointLightComponent.h"
 #include "Components/StaticMeshComponent.h"
 #include "Kismet/GameplayStatics.h"
@@ -22,6 +23,12 @@ AAgrarianCampfire::AAgrarianCampfire()
 	FireLight->SetIntensity(0.0f);
 	FireLight->SetAttenuationRadius(WarmthRadius);
 	FireLight->SetLightColor(FLinearColor(1.0f, 0.45f, 0.18f));
+
+	SmokeEffect = CreateDefaultSubobject<UParticleSystemComponent>(TEXT("SmokeEffect"));
+	SmokeEffect->SetupAttachment(RootComponent);
+	SmokeEffect->bAutoActivate = false;
+	SmokeEffect->SetRelativeLocation(FVector(0.0f, 0.0f, 80.0f));
+	SmokeEffect->SetVisibility(false);
 }
 
 void AAgrarianCampfire::Tick(float DeltaSeconds)
@@ -140,6 +147,19 @@ void AAgrarianCampfire::UpdateVisualState()
 	{
 		FireLight->SetIntensity(bLit ? 4200.0f : 0.0f);
 	}
+
+	if (SmokeEffect)
+	{
+		SmokeEffect->SetVisibility(bLit);
+		if (bLit)
+		{
+			SmokeEffect->ActivateSystem();
+		}
+		else
+		{
+			SmokeEffect->DeactivateSystem();
+		}
+	}
 }
 
 void AAgrarianCampfire::WarmNearbyCharacters(float DeltaSeconds)

Source/AgrarianGame/AgrarianCampfire.h

@@ -8,6 +8,7 @@
 #include "AgrarianCampfire.generated.h"
 
 class UPointLightComponent;
+class UParticleSystemComponent;
 class UStaticMeshComponent;
 
 UCLASS(Blueprintable)
@@ -27,6 +28,9 @@ public:
 	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Agrarian|Fire")
 	TObjectPtr<UPointLightComponent> FireLight;
 
+	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Agrarian|Fire|Effects")
+	TObjectPtr<UParticleSystemComponent> SmokeEffect;
+
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, ReplicatedUsing = OnRep_FireState, Category = "Agrarian|Fire")
 	bool bLit = false;