fix(brain): edge mesh invisible — drop layer-1 assignment, bump base opacity

Camera renders default layer 0 only; edge mesh was on BRAIN_LAYERS.BLOOM
(layer 1) so the camera never saw it. Three.js layers and the
postprocessing SelectiveBloomEffect Selection are different mechanisms —
the bloom mask is the Selection (markBloom + refreshBloomSelection),
not three.js layers. Edges stay on layer 0 like everything else, and
bloom emphasis is handled purely by Selection.

Also raised PulseShader baseOpacity from 0.18 to 0.42 so static-rest
edges read clearly against the near-black backdrop without depending on
bloom contribution.

Author: AdityaVG13

desktop/cortex-control-center/src/BrainVisualizer.jsx

@@ -345,7 +345,6 @@ function BrainVisualizerComponent({ api = null, cortexBase = "http://127.0.0.1:7
     });
 
     if (mesh) {
-      assignLayer(mesh, BRAIN_LAYERS.BLOOM);
       markBloom(mesh, true);
       scene.add(mesh);
       edgeMeshRef.current = mesh;

desktop/cortex-control-center/src/brain-visualizer.test.js

@@ -157,10 +157,10 @@ describe("Brain visualizer", () => {
     expect(edgeMesh).toContain("brainEdgeMesh: true");
   });
 
-  it("BrainVisualizer mounts the merged edge mesh and ticks the pulse uniform each frame", () => {
+  it("BrainVisualizer mounts the merged edge mesh on the default layer and ticks pulse each frame", () => {
     expect(source).toContain("import { buildEdgeMesh, disposeEdgeMesh, tickEdgeMaterialTime }");
     expect(source).toContain("buildEdgeMesh(graphData.links, nodesById,");
-    expect(source).toContain("assignLayer(mesh, BRAIN_LAYERS.BLOOM)");
+    expect(source).not.toContain("assignLayer(mesh, BRAIN_LAYERS.BLOOM)");
     expect(source).toContain("markBloom(mesh, true)");
     expect(source).toContain("tickEdgeMaterialTime(mesh, elapsedSec)");
     expect(source).toContain("disposeEdgeMesh(edgeMeshRef.current)");

desktop/cortex-control-center/src/brain/EdgeMesh.js

@@ -76,6 +76,7 @@ export function buildEdgeMesh(links, nodesById, options = {}) {
     activationCount: edgeCount,
     baseColor: options.baseColor,
     pulseColor: options.pulseColor,
+    baseOpacity: options.baseOpacity ?? 0.42,
   });
 
   const mesh = new THREE.LineSegments(geometry, material);