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+// ═══════════════════════════════════════════
+//  PROJECT MNEMOSYNE — AMBIENT PARTICLE SYSTEM
+// ═══════════════════════════════════════════
+//
+// Memory activity visualization via Three.js Points.
+// Three particle modes:
+//   1. Spawn burst — 20 particles on new fact, 2s fade
+//   2. Access trail — 10 particles streaming to crystal
+//   3. Ambient dust — 200 particles, slow cosmic drift
+//
+// Category colors for all particles.
+// Total budget: < 500 particles at any time.
+//
+// Usage from app.js:
+//   import { MemoryParticles } from './nexus/components/memory-particles.js';
+//   MemoryParticles.init(scene);
+//   MemoryParticles.onMemoryPlaced(position, category);
+//   MemoryParticles.onMemoryAccessed(fromPos, toPos, category);
+//   MemoryParticles.update(delta);
+// ═══════════════════════════════════════════
+
+const MemoryParticles = (() => {
+  let _scene = null;
+  let _initialized = false;
+
+  // ─── CATEGORY COLORS ──────────────────────
+  const CATEGORY_COLORS = {
+    engineering:  new THREE.Color(0x4af0c0),
+    social:       new THREE.Color(0x7b5cff),
+    knowledge:    new THREE.Color(0xffd700),
+    projects:     new THREE.Color(0xff4466),
+    working:      new THREE.Color(0x00ff88),
+    archive:      new THREE.Color(0x334455),
+    user_pref:    new THREE.Color(0xffd700),
+    project:      new THREE.Color(0x4488ff),
+    tool_knowledge: new THREE.Color(0x44ff88),
+    general:      new THREE.Color(0x8899aa),
+  };
+  const DEFAULT_COLOR = new THREE.Color(0x8899bb);
+
+  // ─── PARTICLE BUDGETS ─────────────────────
+  const MAX_BURST_PARTICLES = 20;   // per spawn event
+  const MAX_TRAIL_PARTICLES = 10;   // per access event
+  const AMBIENT_COUNT       = 200;  // always-on dust
+  const MAX_ACTIVE_BURSTS   = 8;    // max concurrent burst groups
+  const MAX_ACTIVE_TRAILS   = 5;    // max concurrent trail groups
+
+  // ─── ACTIVE PARTICLE GROUPS ───────────────
+  let _bursts = [];   // { points, velocities, life, maxLife }
+  let _trails = [];   // { points, velocities, life, maxLife, target }
+  let _ambientPoints = null;
+
+  // ─── HELPERS ──────────────────────────────
+  function _getCategoryColor(category) {
+    return CATEGORY_COLORS[category] || DEFAULT_COLOR;
+  }
+
+  // ═══ AMBIENT DUST ═════════════════════════
+  function _createAmbient() {
+    const geo = new THREE.BufferGeometry();
+    const positions = new Float32Array(AMBIENT_COUNT * 3);
+    const colors = new Float32Array(AMBIENT_COUNT * 3);
+    const sizes = new Float32Array(AMBIENT_COUNT);
+
+    // Distribute across the world
+    for (let i = 0; i < AMBIENT_COUNT; i++) {
+      positions[i * 3]     = (Math.random() - 0.5) * 50;
+      positions[i * 3 + 1] = Math.random() * 18 + 1;
+      positions[i * 3 + 2] = (Math.random() - 0.5) * 50;
+
+      // Subtle category-tinted colors
+      const categories = Object.keys(CATEGORY_COLORS);
+      const cat = categories[Math.floor(Math.random() * categories.length)];
+      const col = _getCategoryColor(cat).clone().multiplyScalar(0.4 + Math.random() * 0.3);
+      colors[i * 3]     = col.r;
+      colors[i * 3 + 1] = col.g;
+      colors[i * 3 + 2] = col.b;
+
+      sizes[i] = 0.02 + Math.random() * 0.04;
+    }
+
+    geo.setAttribute('position', new THREE.BufferAttribute(positions, 3));
+    geo.setAttribute('color', new THREE.BufferAttribute(colors, 3));
+    geo.setAttribute('size', new THREE.BufferAttribute(sizes, 1));
+
+    const mat = new THREE.ShaderMaterial({
+      uniforms: { uTime: { value: 0 } },
+      vertexShader: `
+        attribute float size;
+        attribute vec3 color;
+        varying vec3 vColor;
+        varying float vAlpha;
+        uniform float uTime;
+        void main() {
+          vColor = color;
+          vec3 pos = position;
+          // Slow cosmic drift
+          pos.x += sin(uTime * 0.08 + position.y * 0.3) * 0.5;
+          pos.y += sin(uTime * 0.05 + position.z * 0.2) * 0.3;
+          pos.z += cos(uTime * 0.06 + position.x * 0.25) * 0.4;
+          vec4 mv = modelViewMatrix * vec4(pos, 1.0);
+          gl_PointSize = size * 250.0 / -mv.z;
+          gl_Position = projectionMatrix * mv;
+          // Fade with distance
+          vAlpha = smoothstep(40.0, 10.0, -mv.z) * 0.5;
+        }
+      `,
+      fragmentShader: `
+        varying vec3 vColor;
+        varying float vAlpha;
+        void main() {
+          float d = length(gl_PointCoord - 0.5);
+          if (d > 0.5) discard;
+          float alpha = smoothstep(0.5, 0.05, d);
+          gl_FragColor = vec4(vColor, alpha * vAlpha);
+        }
+      `,
+      transparent: true,
+      depthWrite: false,
+      blending: THREE.AdditiveBlending,
+    });
+
+    _ambientPoints = new THREE.Points(geo, mat);
+    _scene.add(_ambientPoints);
+  }
+
+  // ═══ BURST EFFECT ═════════════════════════
+  function _createBurst(position, category) {
+    const count = MAX_BURST_PARTICLES;
+    const geo = new THREE.BufferGeometry();
+    const positions = new Float32Array(count * 3);
+    const colors = new Float32Array(count * 3);
+    const sizes = new Float32Array(count);
+    const velocities = [];
+    const col = _getCategoryColor(category);
+
+    for (let i = 0; i < count; i++) {
+      positions[i * 3]     = position.x;
+      positions[i * 3 + 1] = position.y;
+      positions[i * 3 + 2] = position.z;
+
+      colors[i * 3]     = col.r;
+      colors[i * 3 + 1] = col.g;
+      colors[i * 3 + 2] = col.b;
+
+      sizes[i] = 0.06 + Math.random() * 0.06;
+
+      // Random outward velocity
+      const theta = Math.random() * Math.PI * 2;
+      const phi = Math.random() * Math.PI;
+      const speed = 1.5 + Math.random() * 2.5;
+      velocities.push(
+        Math.sin(phi) * Math.cos(theta) * speed,
+        Math.cos(phi) * speed * 0.8 + 1.0,  // bias upward
+        Math.sin(phi) * Math.sin(theta) * speed
+      );
+    }
+
+    geo.setAttribute('position', new THREE.BufferAttribute(positions, 3));
+    geo.setAttribute('color', new THREE.BufferAttribute(colors, 3));
+    geo.setAttribute('size', new THREE.BufferAttribute(sizes, 1));
+
+    const mat = new THREE.ShaderMaterial({
+      uniforms: { uOpacity: { value: 1.0 } },
+      vertexShader: `
+        attribute float size;
+        attribute vec3 color;
+        varying vec3 vColor;
+        uniform float uOpacity;
+        void main() {
+          vColor = color;
+          vec4 mv = modelViewMatrix * vec4(position, 1.0);
+          gl_PointSize = size * 300.0 / -mv.z;
+          gl_Position = projectionMatrix * mv;
+        }
+      `,
+      fragmentShader: `
+        varying vec3 vColor;
+        uniform float uOpacity;
+        void main() {
+          float d = length(gl_PointCoord - 0.5);
+          if (d > 0.5) discard;
+          float alpha = smoothstep(0.5, 0.05, d);
+          gl_FragColor = vec4(vColor, alpha * uOpacity);
+        }
+      `,
+      transparent: true,
+      depthWrite: false,
+      blending: THREE.AdditiveBlending,
+    });
+
+    const points = new THREE.Points(geo, mat);
+    _scene.add(points);
+
+    _bursts.push({
+      points,
+      velocities,
+      life: 0,
+      maxLife: 2.0,  // 2s fade
+    });
+
+    // Cap active bursts
+    while (_bursts.length > MAX_ACTIVE_BURSTS) {
+      _removeBurst(0);
+    }
+  }
+
+  function _removeBurst(idx) {
+    const burst = _bursts[idx];
+    if (burst.points.parent) burst.points.parent.remove(burst.points);
+    burst.points.geometry.dispose();
+    burst.points.material.dispose();
+    _bursts.splice(idx, 1);
+  }
+
+  // ═══ TRAIL EFFECT ═════════════════════════
+  function _createTrail(fromPos, toPos, category) {
+    const count = MAX_TRAIL_PARTICLES;
+    const geo = new THREE.BufferGeometry();
+    const positions = new Float32Array(count * 3);
+    const colors = new Float32Array(count * 3);
+    const sizes = new Float32Array(count);
+    const velocities = [];
+    const col = _getCategoryColor(category);
+
+    for (let i = 0; i < count; i++) {
+      // Stagger start positions along the path
+      const t = Math.random();
+      positions[i * 3]     = fromPos.x + (toPos.x - fromPos.x) * t + (Math.random() - 0.5) * 0.5;
+      positions[i * 3 + 1] = fromPos.y + (toPos.y - fromPos.y) * t + (Math.random() - 0.5) * 0.5;
+      positions[i * 3 + 2] = fromPos.z + (toPos.z - fromPos.z) * t + (Math.random() - 0.5) * 0.5;
+
+      colors[i * 3]     = col.r;
+      colors[i * 3 + 1] = col.g;
+      colors[i * 3 + 2] = col.b;
+
+      sizes[i] = 0.04 + Math.random() * 0.04;
+
+      // Velocity toward target with slight randomness
+      const dx = toPos.x - fromPos.x;
+      const dy = toPos.y - fromPos.y;
+      const dz = toPos.z - fromPos.z;
+      const len = Math.sqrt(dx * dx + dy * dy + dz * dz) || 1;
+      const speed = 2.0 + Math.random() * 1.5;
+      velocities.push(
+        (dx / len) * speed + (Math.random() - 0.5) * 0.5,
+        (dy / len) * speed + (Math.random() - 0.5) * 0.5,
+        (dz / len) * speed + (Math.random() - 0.5) * 0.5
+      );
+    }
+
+    geo.setAttribute('position', new THREE.BufferAttribute(positions, 3));
+    geo.setAttribute('color', new THREE.BufferAttribute(colors, 3));
+    geo.setAttribute('size', new THREE.BufferAttribute(sizes, 1));
+
+    const mat = new THREE.ShaderMaterial({
+      uniforms: { uOpacity: { value: 1.0 } },
+      vertexShader: `
+        attribute float size;
+        attribute vec3 color;
+        varying vec3 vColor;
+        uniform float uOpacity;
+        void main() {
+          vColor = color;
+          vec4 mv = modelViewMatrix * vec4(position, 1.0);
+          gl_PointSize = size * 280.0 / -mv.z;
+          gl_Position = projectionMatrix * mv;
+        }
+      `,
+      fragmentShader: `
+        varying vec3 vColor;
+        uniform float uOpacity;
+        void main() {
+          float d = length(gl_PointCoord - 0.5);
+          if (d > 0.5) discard;
+          float alpha = smoothstep(0.5, 0.05, d);
+          gl_FragColor = vec4(vColor, alpha * uOpacity);
+        }
+      `,
+      transparent: true,
+      depthWrite: false,
+      blending: THREE.AdditiveBlending,
+    });
+
+    const points = new THREE.Points(geo, mat);
+    _scene.add(points);
+
+    _trails.push({
+      points,
+      velocities,
+      life: 0,
+      maxLife: 1.5,  // 1.5s trail
+      target: toPos.clone(),
+    });
+
+    // Cap active trails
+    while (_trails.length > MAX_ACTIVE_TRAILS) {
+      _removeTrail(0);
+    }
+  }
+
+  function _removeTrail(idx) {
+    const trail = _trails[idx];
+    if (trail.points.parent) trail.points.parent.remove(trail.points);
+    trail.points.geometry.dispose();
+    trail.points.material.dispose();
+    _trails.splice(idx, 1);
+  }
+
+  // ═══ PUBLIC API ═══════════════════════════
+  function init(scene) {
+    _scene = scene;
+    _initialized = true;
+    _createAmbient();
+    console.info('[Mnemosyne] Ambient particle system initialized —', AMBIENT_COUNT, 'dust particles');
+  }
+
+  function onMemoryPlaced(position, category) {
+    if (!_initialized) return;
+    const pos = position instanceof THREE.Vector3 ? position : new THREE.Vector3(position.x, position.y, position.z);
+    _createBurst(pos, category);
+  }
+
+  function onMemoryAccessed(fromPosition, toPosition, category) {
+    if (!_initialized) return;
+    const from = fromPosition instanceof THREE.Vector3 ? fromPosition : new THREE.Vector3(fromPosition.x, fromPosition.y, fromPosition.z);
+    const to = toPosition instanceof THREE.Vector3 ? toPosition : new THREE.Vector3(toPosition.x, toPosition.y, toPosition.z);
+    _createTrail(from, to, category);
+  }
+
+  function update(delta) {
+    if (!_initialized) return;
+
+    // Update ambient dust
+    if (_ambientPoints && _ambientPoints.material.uniforms) {
+      _ambientPoints.material.uniforms.uTime.value += delta;
+    }
+
+    // Update bursts
+    for (let i = _bursts.length - 1; i >= 0; i--) {
+      const burst = _bursts[i];
+      burst.life += delta;
+      const t = burst.life / burst.maxLife;
+
+      if (t >= 1.0) {
+        _removeBurst(i);
+        continue;
+      }
+
+      const pos = burst.points.geometry.attributes.position.array;
+      for (let j = 0; j < MAX_BURST_PARTICLES; j++) {
+        pos[j * 3]     += burst.velocities[j * 3] * delta;
+        pos[j * 3 + 1] += burst.velocities[j * 3 + 1] * delta;
+        pos[j * 3 + 2] += burst.velocities[j * 3 + 2] * delta;
+
+        // Gravity + drag
+        burst.velocities[j * 3 + 1] -= delta * 0.5;
+        burst.velocities[j * 3]     *= 0.98;
+        burst.velocities[j * 3 + 1] *= 0.98;
+        burst.velocities[j * 3 + 2] *= 0.98;
+      }
+      burst.points.geometry.attributes.position.needsUpdate = true;
+      burst.points.material.uniforms.uOpacity.value = 1.0 - t;
+    }
+
+    // Update trails
+    for (let i = _trails.length - 1; i >= 0; i--) {
+      const trail = _trails[i];
+      trail.life += delta;
+      const t = trail.life / trail.maxLife;
+
+      if (t >= 1.0) {
+        _removeTrail(i);
+        continue;
+      }
+
+      const pos = trail.points.geometry.attributes.position.array;
+      for (let j = 0; j < MAX_TRAIL_PARTICLES; j++) {
+        pos[j * 3]     += trail.velocities[j * 3] * delta;
+        pos[j * 3 + 1] += trail.velocities[j * 3 + 1] * delta;
+        pos[j * 3 + 2] += trail.velocities[j * 3 + 2] * delta;
+      }
+      trail.points.geometry.attributes.position.needsUpdate = true;
+      trail.points.material.uniforms.uOpacity.value = 1.0 - t * t;
+    }
+  }
+
+  function getActiveParticleCount() {
+    let total = AMBIENT_COUNT;
+    _bursts.forEach(b => { total += MAX_BURST_PARTICLES; });
+    _trails.forEach(t => { total += MAX_TRAIL_PARTICLES; });
+    return total;
+  }
+
+  return {
+    init,
+    onMemoryPlaced,
+    onMemoryAccessed,
+    update,
+    getActiveParticleCount,
+  };
+})();
+
+export { MemoryParticles };