Optimize lexical timing diagnostics and suppress dense WHERE diffusion edges

modules/story-summary/vector/retrieval/diffusion.js

@@ -53,6 +53,9 @@ const CONFIG = {
         where: 0.15,        // location exact match      — binary
         how: 0.30,          // action-term co-occurrence — Jaccard
     },
+    WHERE_MAX_GROUP_SIZE: 16,   // skip location-only pair expansion for over-common places
+    WHERE_FREQ_DAMP_PIVOT: 6,   // location freq <= pivot keeps full WHERE score
+    WHERE_FREQ_DAMP_MIN: 0.20,  // lower bound for damped WHERE contribution
 
     // Post-verification (Cosine Gate)
     COSINE_GATE: 0.45,      // min cosine(queryVector, stateVector)
@@ -275,11 +278,24 @@ function buildGraph(allAtoms, excludeEntities = new Set()) {
 
     const features = extractAllFeatures(allAtoms, excludeEntities);
     const { entityIndex, locationIndex } = buildInvertedIndices(features);
+    const locationFreq = new Map();
+    for (const [loc, indices] of locationIndex.entries()) {
+        locationFreq.set(loc, indices.length);
+    }
 
     // Candidate pairs: share ≥1 entity or same location
     const pairSet = new Set();
     collectPairsFromIndex(entityIndex, pairSet, N);
-    collectPairsFromIndex(locationIndex, pairSet, N);
+    let skippedLocationGroups = 0;
+    for (const [loc, indices] of locationIndex.entries()) {
+        if (!loc) continue;
+        if (indices.length > CONFIG.WHERE_MAX_GROUP_SIZE) {
+            skippedLocationGroups++;
+            continue;
+        }
+        const oneLocMap = new Map([[loc, indices]]);
+        collectPairsFromIndex(oneLocMap, pairSet, N);
+    }
 
     // Compute three-channel edge weights for all candidates
     const neighbors = Array.from({ length: N }, () => []);
@@ -294,7 +310,15 @@ function buildGraph(allAtoms, excludeEntities = new Set()) {
         const fj = features[j];
 
         const wWhat = overlapCoefficient(fi.interactionPairs, fj.interactionPairs);
-        const wWhere = (fi.location && fi.location === fj.location) ? 1.0 : 0.0;
+        let wWhere = 0.0;
+        if (fi.location && fi.location === fj.location) {
+            const freq = locationFreq.get(fi.location) || 1;
+            const damp = Math.max(
+                CONFIG.WHERE_FREQ_DAMP_MIN,
+                Math.min(1, CONFIG.WHERE_FREQ_DAMP_PIVOT / Math.max(1, freq))
+            );
+            wWhere = damp;
+        }
         const wHow = jaccard(fi.actionTerms, fj.actionTerms);
 
         const weight =
@@ -318,6 +342,7 @@ function buildGraph(allAtoms, excludeEntities = new Set()) {
     xbLog.info(MODULE_ID,
         `Graph: ${N} nodes, ${edgeCount} edges ` +
         `(what=${channelStats.what} where=${channelStats.where} how=${channelStats.how}) ` +
+        `(whereSkippedGroups=${skippedLocationGroups}) ` +
         `(${buildTime}ms)`
     );