fix(anchor): serialize frame actions and self-heal stale L1 boundary

modules/story-summary/story-summary.js

@@ -367,6 +367,18 @@ async function handleAnchorGenerate() {
             postToFrame({ type: "ANCHOR_GEN_PROGRESS", current, total, message });
         });
 
+        // Self-heal: if chunks are empty but boundary looks "already built",
+        // reset boundary so incremental L1 rebuild can start from floor 0.
+        const [meta, storageStats] = await Promise.all([
+            getMeta(chatId),
+            getStorageStats(chatId),
+        ]);
+        const lastFloor = (chat?.length || 0) - 1;
+        if (storageStats.chunks === 0 && lastFloor >= 0 && (meta.lastChunkFloor ?? -1) >= lastFloor) {
+            await updateMeta(chatId, { lastChunkFloor: -1 });
+            xbLog.warn(MODULE_ID, "Detected empty L1 chunks with full boundary, reset lastChunkFloor=-1");
+        }
+
         postToFrame({ type: "ANCHOR_GEN_PROGRESS", current: 0, total: 1, message: "向量化 L1..." });
         const chunkResult = await buildIncrementalChunks({ vectorConfig: vectorCfg });
 
@@ -1157,7 +1169,7 @@ function updateFrameStatsAfterSummary(endMesId, merged) {
 // iframe 消息处理
 // ═══════════════════════════════════════════════════════════════════════════
 
-function handleFrameMessage(event) {
+async function handleFrameMessage(event) {
     const iframe = document.getElementById("xiaobaix-story-summary-iframe");
     if (!isTrustedMessage(event, iframe, "LittleWhiteBox-StoryFrame")) return;
 
@@ -1212,7 +1224,7 @@ function handleFrameMessage(event) {
             break;
 
         case "VECTOR_CLEAR":
-            handleClearVectors();
+            await handleClearVectors();
             break;
 
         case "VECTOR_CANCEL_GENERATE":
@@ -1223,11 +1235,11 @@ function handleFrameMessage(event) {
             break;
 
         case "ANCHOR_GENERATE":
-            handleAnchorGenerate();
+            await handleAnchorGenerate();
             break;
 
         case "ANCHOR_CLEAR":
-            handleAnchorClear();
+            await handleAnchorClear();
             break;
 
         case "ANCHOR_CANCEL":