fix(insight): bound graph look-ahead allocation

Clamp cluster look-ahead values at the shared core boundary so invalid inputs cannot create oversized candidate matrices. Add a regression test that keeps oversized values equivalent to the supported maximum.

packages/core/src/query/advanced/__tests__/social.test.ts

@@ -213,6 +213,15 @@ describe('social analysis', () => {
     )
   })
 
+  it('caps oversized look-ahead values before allocating candidate indexes', () => {
+    const messages = Array.from({ length: 12 }, (_, index) => ({ senderId: index + 1, ts: 100 + index }))
+
+    assert.deepEqual(
+      accumulateCoOccurrencePairBatches([messages], { lookAhead: 100_000 }),
+      accumulateCoOccurrencePairBatches([messages], { lookAhead: 10 })
+    )
+  })
+
   it('keeps large streamed aggregation identical to the in-memory algorithm', () => {
     const senderPattern = [1, 1, 2, 3, 2, 4, 5]
     const messages = Array.from({ length: 100_005 }, (_, index) => ({

packages/core/src/query/advanced/social.ts

@@ -309,9 +309,22 @@ export interface SelectedCoOccurrencePairStats extends CoOccurrencePairStats {
 }
 
 const DEFAULT_CLUSTER_OPTIONS = { lookAhead: 3, decaySeconds: 120, topEdges: 100 }
+const MAX_CLUSTER_LOOK_AHEAD = 10
 const DEFAULT_SELECTED_PROXIMITY_MAX_GAP_SECONDS = 1800
 const CO_OCCURRENCE_MESSAGE_BATCH_SIZE = 20_000
 
+function resolveClusterOptions(options?: ClusterGraphOptions): Required<ClusterGraphOptions> {
+  const requestedLookAhead = options?.lookAhead ?? DEFAULT_CLUSTER_OPTIONS.lookAhead
+  const lookAhead = Number.isFinite(requestedLookAhead)
+    ? Math.min(MAX_CLUSTER_LOOK_AHEAD, Math.max(0, Math.ceil(requestedLookAhead)))
+    : DEFAULT_CLUSTER_OPTIONS.lookAhead
+  return {
+    lookAhead,
+    decaySeconds: options?.decaySeconds ?? DEFAULT_CLUSTER_OPTIONS.decaySeconds,
+    topEdges: options?.topEdges ?? DEFAULT_CLUSTER_OPTIONS.topEdges,
+  }
+}
+
 function roundNum(value: number, digits = 4): number {
   const factor = 10 ** digits
   return Math.round(value * factor) / factor
@@ -325,7 +338,7 @@ export function accumulateCoOccurrencePairs(
   messages: CoOccurrenceMessage[],
   options?: ClusterGraphOptions
 ): CoOccurrencePairStats[] {
-  const opts = { ...DEFAULT_CLUSTER_OPTIONS, ...options }
+  const opts = resolveClusterOptions(options)
   const pairStatsBySource = new Map<number, Map<number, CoOccurrencePairStats>>()
   const pairs: CoOccurrencePairStats[] = []
 
@@ -398,8 +411,8 @@ function accumulateCoOccurrenceColumns(
   timestamps: Float64Array,
   options?: ClusterGraphOptions
 ): CoOccurrencePairStats[] {
-  const opts = { ...DEFAULT_CLUSTER_OPTIONS, ...options }
-  const lookAhead = Math.max(0, Math.ceil(opts.lookAhead))
+  const opts = resolveClusterOptions(options)
+  const lookAhead = opts.lookAhead
   const candidateIndexes = buildDistinctSpeakerLookAhead(senderIds.length, (index) => senderIds[index], lookAhead)
   const pairStatsBySource = new Map<number, Map<number, CoOccurrencePairStats>>()
   const pairs: CoOccurrencePairStats[] = []
@@ -459,8 +472,8 @@ export function accumulateSelectedCoOccurrencePairs(
   selectedPairs: Array<readonly [number, number]>,
   options?: ClusterGraphOptions & { maxAnchorsPerPair?: number; maxGapSeconds?: number }
 ): SelectedCoOccurrencePairStats[] {
-  const opts = { ...DEFAULT_CLUSTER_OPTIONS, ...options }
-  const lookAhead = Math.max(0, Math.ceil(opts.lookAhead))
+  const opts = resolveClusterOptions(options)
+  const lookAhead = opts.lookAhead
   const maxAnchorsPerPair = Math.max(0, Math.floor(options?.maxAnchorsPerPair ?? 2))
   const maxGapSeconds = Math.max(0, options?.maxGapSeconds ?? DEFAULT_SELECTED_PROXIMITY_MAX_GAP_SECONDS)
   const selectedKeys = new Set(selectedPairs.map(([left, right]) => clusterPairKey(left, right)))
@@ -615,7 +628,7 @@ export function getClusterGraph(
   filter?: TimeFilter,
   options?: ClusterGraphOptions
 ): ClusterGraphData {
-  const opts = { ...DEFAULT_CLUSTER_OPTIONS, ...options }
+  const opts = resolveClusterOptions(options)
   const emptyResult: ClusterGraphData = {
     nodes: [],
     links: [],