feat(mnemosyne): integrate spatial memory schema with orb system

- Loads spatial-memory-schema.json on init
- Maps memory categories to rooms (Library, Workshop, Armory, Commons)
- Adds spawnCategorizedOrb() for category-based placement
- Adds drawHolographicThread() for orb connections
- Adds spawnWithRoomTransition() for animated room placement
- Animates holographic threads and room transitions in game loop

Supersedes #1150 (blocked by branch protection).

app.js

@@ -2576,6 +2576,8 @@ function gameLoop() {
   // Project Mnemosyne - Memory Orb Animation
   if (typeof animateMemoryOrbs === 'function') {
     animateMemoryOrbs(delta);
+    animateHolographicThreads(delta);
+    animateRoomTransitions(delta);
   }
 
 
@@ -3090,7 +3092,232 @@ function spawnRetrievalOrbs(results, center) {
     });
 }
 
+// ═══════════════════════════════════════════
+//  MNEMOSYNE — SPATIAL MEMORY INTEGRATION
+// ═══════════════════════════════════════════
+
+// Spatial memory schema state (loaded async)
+let spatialMemorySchema = null;
+const holographicThreads = []; // Active thread meshes
+
+/**
+ * Load the spatial memory schema and store it for room mapping.
+ * Called during init. Falls back gracefully if schema unavailable.
+ */
+async function loadSpatialMemorySchema() {
+    try {
+        const resp = await fetch('/spatial-memory-schema.json');
+        if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
+        spatialMemorySchema = await resp.json();
+        console.info('[Mnemosyne] Spatial memory schema loaded:',
+            Object.keys(spatialMemorySchema.rooms).length, 'rooms');
+    } catch (err) {
+        console.warn('[Mnemosyne] Could not load spatial schema, using defaults:', err.message);
+        spatialMemorySchema = null;
+    }
+}
+
+/**
+ * Get the room definition for a memory category.
+ * @param {string} category - Memory category (user_pref, project, tool, general)
+ * @returns {object|null} Room definition with spatial_bounds and visual_theme
+ */
+function getRoomForCategory(category) {
+    if (!spatialMemorySchema) return null;
+    for (const [roomId, room] of Object.entries(spatialMemorySchema.rooms)) {
+        if (room.category === category) return { id: roomId, ...room };
+    }
+    // Fallback to commons for unknown categories
+    if (spatialMemorySchema.rooms.commons) {
+        return { id: 'commons', ...spatialMemorySchema.rooms.commons };
+    }
+    return null;
+}
+
+/**
+ * Calculate a random position within a room's spatial bounds.
+ * @param {object} room - Room definition with spatial_bounds
+ * @returns {THREE.Vector3} Position within room bounds
+ */
+function getPositionInRoom(room) {
+    const bounds = room.spatial_bounds;
+    const dims = bounds.dimensions;
+    const center = bounds.center;
+
+    return new THREE.Vector3(
+        center[0] + (Math.random() - 0.5) * dims[0] * 0.8,
+        center[1] + (Math.random() - 0.5) * dims[1] * 0.6 + 1.5, // Float above floor
+        center[2] + (Math.random() - 0.5) * dims[2] * 0.8
+    );
+}
+
+/**
+ * Spawn a categorized memory orb placed in its corresponding room.
+ * Extends spawnMemoryOrb with spatial placement based on category.
+ *
+ * @param {string} category - Memory category (user_pref, project, tool, general)
+ * @param {object} metadata - Memory metadata (source, content, score, etc.)
+ * @param {number} importance - 0-1 importance score (affects size/glow)
+ * @returns {THREE.Mesh} The spawned orb
+ */
+function spawnCategorizedOrb(category, metadata = {}, importance = 0.5) {
+    const room = getRoomForCategory(category);
+    const position = room ? getPositionInRoom(room) : new THREE.Vector3(0, 2, 0);
+
+    // Color from schema trust mapping or room theme
+    let color = 0x4af0c0; // Default cyan
+    if (room && room.visual_theme) {
+        const accent = room.visual_theme.colors?.accent;
+        if (accent) color = parseInt(accent.replace('#', ''), 16);
+    }
+
+    // Size scales with importance
+    const size = 0.2 + importance * 0.5;
+
+    const orb = spawnMemoryOrb(position, color, size, {
+        ...metadata,
+        category: category,
+        room: room ? room.id : 'unknown'
+    });
+
+    return orb;
+}
+
+/**
+ * Draw a holographic thread connecting two memory orbs.
+ * @param {THREE.Mesh} orbA - First orb
+ * @param {THREE.Mesh} orbB - Second orb
+ * @param {number} color - Thread color (default: 0x4af0c0)
+ * @returns {THREE.Line} The thread mesh
+ */
+function drawHolographicThread(orbA, orbB, color = 0x4af0c0) {
+    if (typeof THREE === 'undefined' || !orbA || !orbB) return null;
+
+    const points = [orbA.position.clone(), orbB.position.clone()];
+    const geometry = new THREE.BufferGeometry().setFromPoints(points);
+    const material = new THREE.LineBasicMaterial({
+        color: color,
+        transparent: true,
+        opacity: 0.4,
+        linewidth: 1
+    });
+
+    const thread = new THREE.Line(geometry, material);
+    thread.userData = {
+        type: 'holographic_thread',
+        orbA: orbA,
+        orbB: orbB,
+        createdAt: Date.now()
+    };
+
+    scene.add(thread);
+    holographicThreads.push(thread);
+    return thread;
+}
+
+/**
+ * Update holographic threads to follow their connected orbs.
+ * Called from the animation loop.
+ * @param {number} delta - Time since last frame
+ */
+function animateHolographicThreads(delta) {
+    for (let i = holographicThreads.length - 1; i >= 0; i--) {
+        const thread = holographicThreads[i];
+        if (!thread || !thread.userData) continue;
+
+        const { orbA, orbB } = thread.userData;
+
+        // Remove thread if either orb is gone
+        if (!orbA || !orbA.parent || !orbB || !orbB.parent) {
+            scene.remove(thread);
+            thread.geometry.dispose();
+            thread.material.dispose();
+            holographicThreads.splice(i, 1);
+            continue;
+        }
+
+        // Update line positions to follow orbs
+        const positions = thread.geometry.attributes.position;
+        positions.setXYZ(0, orbA.position.x, orbA.position.y, orbA.position.z);
+        positions.setXYZ(1, orbB.position.x, orbB.position.y, orbB.position.z);
+        positions.needsUpdate = true;
+
+        // Pulse opacity
+        const age = (Date.now() - thread.userData.createdAt) / 1000;
+        thread.material.opacity = 0.3 + Math.sin(age * 2) * 0.1;
+    }
+}
+
+/**
+ * Spawn a memory orb and animate it transitioning to its room.
+ * @param {string} category - Memory category
+ * @param {object} metadata - Memory metadata
+ * @param {number} importance - 0-1 importance score
+ * @param {THREE.Vector3} startPos - Starting position (default: above avatar)
+ * @returns {THREE.Mesh} The orb (already in transit)
+ */
+function spawnWithRoomTransition(category, metadata = {}, importance = 0.5, startPos = null) {
+    if (!startPos) startPos = new THREE.Vector3(0, 2, 0);
+
+    const room = getRoomForCategory(category);
+    const endPos = room ? getPositionInRoom(room) : new THREE.Vector3(0, 2, 0);
+
+    let color = 0x4af0c0;
+    if (room && room.visual_theme) {
+        const accent = room.visual_theme.colors?.accent;
+        if (accent) color = parseInt(accent.replace('#', ''), 16);
+    }
+
+    const size = 0.2 + importance * 0.5;
+
+    // Spawn at start position
+    const orb = spawnMemoryOrb(startPos, color, size, {
+        ...metadata,
+        category: category,
+        room: room ? room.id : 'unknown',
+        transitioning: true,
+        targetPos: endPos,
+        transitionStart: Date.now(),
+        transitionDuration: 2000 + Math.random() * 1000
+    });
+
+    return orb;
+}
+
+/**
+ * Animate room transitions for orbs that are in transit.
+ * @param {number} delta - Time since last frame
+ */
+function animateRoomTransitions(delta) {
+    for (const orb of memoryOrbs) {
+        if (!orb.userData?.transitioning || !orb.userData?.targetPos) continue;
+
+        const elapsed = Date.now() - orb.userData.transitionStart;
+        const duration = orb.userData.transitionDuration;
+        const progress = Math.min(1, elapsed / duration);
+
+        // Ease-out cubic
+        const eased = 1 - Math.pow(1 - progress, 3);
+
+        orb.position.lerpVectors(
+            orb.position, // Current (already partially moved)
+            orb.userData.targetPos,
+            eased * 0.05 // Smooth interpolation factor per frame
+        );
+
+        if (progress >= 1) {
+            orb.position.copy(orb.userData.targetPos);
+            orb.userData.transitioning = false;
+            delete orb.userData.targetPos;
+            delete orb.userData.transitionStart;
+            delete orb.userData.transitionDuration;
+        }
+    }
+}
+
+
 init().then(() => {
+  loadSpatialMemorySchema();
   createAshStorm();
   createPortalTunnel();
   fetchGiteaData();