tune recall threshold and increase distant evidence budget

modules/story-summary/generate/prompt.js

@@ -49,7 +49,7 @@ const CONSTRAINT_MAX = 2000;
 const ARCS_MAX = 1500;
 const EVENT_BUDGET_MAX = 5000;
 const RELATED_EVENT_MAX = 500;
-const SUMMARIZED_EVIDENCE_MAX = 1500;
+const SUMMARIZED_EVIDENCE_MAX = 2000;
 const UNSUMMARIZED_EVIDENCE_MAX = 2000;
 const TOP_N_STAR = 5;
 
@@ -949,6 +949,8 @@ async function buildVectorPrompt(store, recallResult, causalById, focusCharacter
     const candidates = [...eventHits].sort((a, b) => (b.similarity || 0) - (a.similarity || 0));
     const eventBudget = { used: 0, max: Math.min(EVENT_BUDGET_MAX, total.max - total.used) };
     const relatedBudget = { used: 0, max: RELATED_EVENT_MAX };
+    // Once budget becomes tight, keep high-score L2 summaries and stop attaching evidence.
+    let allowEventEvidence = true;
 
     const selectedDirect = [];
     const selectedRelated = [];
@@ -964,27 +966,39 @@ async function buildVectorPrompt(store, recallResult, causalById, focusCharacter
 
         // 硬规则：RELATED 事件不挂证据（不挂 L0/L1，只保留事件摘要）
         // DIRECT 才允许收集事件内证据组。
-        const evidenceGroups = isDirect
+        const useEvidenceForThisEvent = isDirect && allowEventEvidence;
+        const evidenceGroups = useEvidenceForThisEvent
             ? collectEvidenceGroupsForEvent(e.event, l0Selected, l1ByFloor, usedL0Ids)
             : [];
 
         // 格式化事件（含证据）
         const text = formatEventWithEvidence(e, 0, evidenceGroups, causalById);
         const cost = estimateTokens(text);
+        const fitEventBudget = eventBudget.used + cost <= eventBudget.max;
+        const fitRelatedBudget = isDirect || (relatedBudget.used + cost <= relatedBudget.max);
 
         // 预算检查：整个事件（含证据）作为原子单元
-        if (total.used + cost > total.max) {
+        // 约束：总预算 + 事件预算 + related 子预算（若 applicable）
+        if (total.used + cost > total.max || !fitEventBudget || !fitRelatedBudget) {
             // 尝试不带证据的版本
             const textNoEvidence = formatEventWithEvidence(e, 0, [], causalById);
             const costNoEvidence = estimateTokens(textNoEvidence);
+            const fitEventBudgetNoEvidence = eventBudget.used + costNoEvidence <= eventBudget.max;
+            const fitRelatedBudgetNoEvidence = isDirect || (relatedBudget.used + costNoEvidence <= relatedBudget.max);
 
-            if (total.used + costNoEvidence > total.max) {
+            if (total.used + costNoEvidence > total.max || !fitEventBudgetNoEvidence || !fitRelatedBudgetNoEvidence) {
                 // 归还 usedL0Ids
                 for (const group of evidenceGroups) {
                     for (const l0 of group.l0Atoms) {
                         usedL0Ids.delete(l0.id);
                     }
                 }
+                // Hard cap reached: no-evidence version also cannot fit total/event budget.
+                // Keep ranking semantics (higher-score events first): stop here.
+                if (total.used + costNoEvidence > total.max || !fitEventBudgetNoEvidence) {
+                    break;
+                }
+                // Related sub-budget overflow: skip this related event and continue.
                 continue;
             }
 
@@ -994,6 +1008,10 @@ async function buildVectorPrompt(store, recallResult, causalById, focusCharacter
                     usedL0Ids.delete(l0.id);
                 }
             }
+            // Enter summary-only mode after first budget conflict on evidence.
+            if (useEvidenceForThisEvent && evidenceGroups.length > 0) {
+                allowEventEvidence = false;
+            }
 
             if (isDirect) {
                 selectedDirect.push({