fix: distribute document clusters across canvas instead of clumping

- Exclude 'extends' edges from force simulation (visual-only, no pull)
- Apply same filter in update() to prevent re-adding extends on refresh
- Stronger derives link strength (0.35) to keep memories near parent doc
- Each document forms its own mini-cluster with orbiting memories
- Clusters spread evenly across the entire canvas

packages/memory-graph/src/canvas/simulation.ts

@@ -9,6 +9,11 @@ export class ForceSimulation {
 		this.destroy()
 
 		try {
+			// Only use structural edges (derives, updates) for the force layout.
+			// "extends" edges are visual-only -- they connect documents sharing a
+			// spaceId but should not pull documents together into a single mass.
+			const structuralEdges = edges.filter((e) => e.edgeType !== "extends")
+
 			this.sim = d3
 				.forceSimulation<GraphNode>(nodes)
 				.alphaDecay(FORCE_CONFIG.alphaDecay)
@@ -18,7 +23,7 @@ export class ForceSimulation {
 			this.sim.force(
 				"link",
 				d3
-					.forceLink<GraphNode, GraphEdge>(edges)
+					.forceLink<GraphNode, GraphEdge>(structuralEdges)
 					.id((d) => d.id)
 					.distance((link) =>
 						link.edgeType === "derives"
@@ -30,8 +35,6 @@ export class ForceSimulation {
 							return FORCE_CONFIG.linkStrength.docMemory
 						if (link.edgeType === "updates")
 							return FORCE_CONFIG.linkStrength.version
-						if (link.edgeType === "extends")
-							return FORCE_CONFIG.linkStrength.docDocBase
 						return FORCE_CONFIG.linkStrength.fallback
 					}),
 			)
@@ -70,7 +73,8 @@ export class ForceSimulation {
 		if (!this.sim) return
 		this.sim.nodes(nodes)
 		const linkForce = this.sim.force<d3.ForceLink<GraphNode, GraphEdge>>("link")
-		if (linkForce) linkForce.links(edges)
+		if (linkForce)
+			linkForce.links(edges.filter((e) => e.edgeType !== "extends"))
 	}
 
 	reheat(): void {

packages/memory-graph/src/constants.ts

@@ -9,22 +9,22 @@ export const MEMORY_BORDER_KEYS = {
 
 export const FORCE_CONFIG = {
 	linkStrength: {
-		docMemory: 0.12,
-		version: 0.5,
-		docDocBase: 0.08,
-		fallback: 0.08,
+		docMemory: 0.35,
+		version: 0.6,
+		docDocBase: 0.0,
+		fallback: 0.05,
 	},
 	linkDistance: 300,
-	docMemoryDistance: 220,
-	chargeStrength: -2500,
+	docMemoryDistance: 180,
+	chargeStrength: -2000,
 	collisionRadius: { document: 70, memory: 35 },
 	collisionStrength: 0.7,
-	centeringStrength: 0.08,
+	centeringStrength: 0.06,
 	alphaDecay: 0.025,
 	alphaMin: 0.001,
 	velocityDecay: 0.45,
 	alphaTarget: 0.3,
-	preSettleTicks: 250,
+	preSettleTicks: 150,
 }
 
 export const GRAPH_SETTINGS = {