Fix code review issues: Buffer.from for indexOf, keywordsChanged flag, write chain error handling

Author: Copilot

src/core/cache/fileScanCacheStore.js

@@ -158,12 +158,14 @@ function createFileScanCacheStore({
 
     /**
      * Serializes write operations to prevent corruption.
+     * Previous errors in the chain are swallowed so the next operation can proceed.
      * @param {function(): Promise<void>} fn
      * @returns {Promise<void>}
      */
     function enqueueWrite(fn) {
-        writeChain = writeChain.then(fn, fn);
-        return writeChain;
+        const next = writeChain.then(fn, () => fn());
+        writeChain = next.catch(() => undefined);
+        return next;
     }
 
     return {

src/core/incremental/graphUpdater.js

@@ -140,10 +140,12 @@ function createGraphUpdater({
             }
         }
         // Add new keywords
-        for (const kw of newKeywords) {
+        if (newKeywords.length > 0) {
             keywordsChanged = true;
-            if (!keywordMap.has(kw.keyword)) keywordMap.set(kw.keyword, []);
-            keywordMap.get(kw.keyword).push(kw);
+            for (const kw of newKeywords) {
+                if (!keywordMap.has(kw.keyword)) keywordMap.set(kw.keyword, []);
+                keywordMap.get(kw.keyword).push(kw);
+            }
         }
 
         // --- Update includes ---

src/core/parser/includeScanner.js

@@ -363,7 +363,8 @@ const SMALL_FILE_THRESHOLD = 1024 * 1024; // 1 MB
  */
 function collectIncludeDirectivesFromBuffer(buffer, basePath) {
     // Quick scan: if the buffer doesn't contain '*INCLUDE' at all, skip parsing entirely
-    if (buffer.indexOf('*INCLUDE') === -1) {
+    const INCLUDE_MARKER = Buffer.from('*INCLUDE');
+    if (buffer.indexOf(INCLUDE_MARKER) === -1) {
         return { includeEntries: [], searchPaths: [basePath] };
     }