fix: [PERF] Add quality-tier feature gating for heavy visual effects (closes #706)

app.js

@@ -704,13 +704,13 @@ async function init() {
   createParticles();
   createDustParticles();
   updateLoad(85);
-  createAmbientStructures();
+  if (performanceTier !== "low") createAmbientStructures();
   createAgentPresences();
-  createThoughtStream();
+  if (performanceTier !== "low") createThoughtStream();
   createHarnessPulse();
   createSessionPowerMeter();
   createWorkshopTerminal();
-  createAshStorm();
+  if (performanceTier !== "low") createAshStorm();
   SpatialMemory.init(scene);
   MemoryBirth.init(scene);
   MemoryBirth.wrapSpatialMemory(SpatialMemory);
@@ -730,14 +730,20 @@ async function init() {
   fetchGiteaData();
   setInterval(fetchGiteaData, 30000); // Refresh every 30s
 
-  composer = new EffectComposer(renderer);
-  composer.addPass(new RenderPass(scene, camera));
-  const bloom = new UnrealBloomPass(
-    new THREE.Vector2(window.innerWidth, window.innerHeight),
-    0.6, 0.4, 0.85
-  );
-  composer.addPass(bloom);
-  composer.addPass(new SMAAPass(window.innerWidth, window.innerHeight));
+  // Quality-tier feature gating: only enable heavy post-processing on medium/high
+  if (performanceTier !== 'low') {
+    composer = new EffectComposer(renderer);
+    composer.addPass(new RenderPass(scene, camera));
+    const bloomStrength = performanceTier === 'high' ? 0.6 : 0.35;
+    const bloom = new UnrealBloomPass(
+      new THREE.Vector2(window.innerWidth, window.innerHeight),
+      bloomStrength, 0.4, 0.85
+    );
+    composer.addPass(bloom);
+    composer.addPass(new SMAAPass(window.innerWidth, window.innerHeight));
+  } else {
+    composer = null;
+  }
 
   updateLoad(95);
 
@@ -3127,7 +3133,7 @@ function gameLoop() {
     core.material.emissiveIntensity = 1.5 + Math.sin(elapsed * 2) * 0.5;
   }
 
-  composer.render();
+  if (composer) { composer.render(); } else { renderer.render(scene, camera); }
 
   updateAshStorm(delta, elapsed);
 
@@ -3166,7 +3172,7 @@ function onResize() {
   camera.aspect = w / h;
   camera.updateProjectionMatrix();
   renderer.setSize(w, h);
-  composer.setSize(w, h);
+  if (composer) composer.setSize(w, h);
 }
 
 // ═══ AGENT SIMULATION ═══