feat(rag): add hybrid knowledge rebuild API and script

Add confirm-gated rebuild-hybrid endpoint that drops biz_hybrid, clears
api_document and L0, then force-imports knowledge_base markdown into the
dense+BM25 store. Include PowerShell runner and ops README.

src/main/java/com/superbiz/agent/service/KnowledgeBaseInitService.java

@@ -52,6 +52,42 @@ public class KnowledgeBaseInitService {
     @Autowired
     private KnowledgeIndexService knowledgeIndexService;
 
+    @Autowired
+    private com.superbiz.agent.service.milvus.MilvusHybridKnowledgeStore hybridKnowledgeStore;
+
+    /**
+     * Drop hybrid collection, clear MySQL api_document + L0 memory index,
+     * then force-import all markdown under knowledge.base-path into biz_hybrid.
+     */
+    @Transactional(rollbackFor = Exception.class)
+    public RebuildResult rebuildHybridFromKnowledgeBase() {
+        logger.info("Starting hybrid knowledge rebuild from {}", knowledgeBasePath);
+        RebuildResult rebuild = new RebuildResult();
+        rebuild.setBasePath(knowledgeBasePath);
+        rebuild.setCollection(hybridKnowledgeStore.collectionName());
+
+        long mysqlBefore = apiDocumentRepository.count();
+        rebuild.setMysqlDocumentsBefore(mysqlBefore);
+
+        Map<String, Object> milvus = hybridKnowledgeStore.dropAndRecreateCollection();
+        rebuild.setMilvus(milvus);
+
+        apiDocumentRepository.deleteAll();
+        apiDocumentRepository.flush();
+        knowledgeIndexService.clearIndex();
+        rebuild.setMysqlDocumentsAfterClear(apiDocumentRepository.count());
+        rebuild.setL0IndexSizeAfterClear(knowledgeIndexService.getIndexSize());
+
+        InitResult init = initializeKnowledgeBase(true);
+        rebuild.setInit(init);
+        rebuild.setL0IndexSizeAfterInit(knowledgeIndexService.getIndexSize());
+        rebuild.setMysqlDocumentsAfterInit(apiDocumentRepository.count());
+        rebuild.setSuccess(init.getFailed() == 0 && init.getInserted() > 0);
+        logger.info("Hybrid knowledge rebuild finished: success={}, inserted={}, failed={}",
+                rebuild.isSuccess(), init.getInserted(), init.getFailed());
+        return rebuild;
+    }
+
     /**
      * 初始化知识库
      *
@@ -131,16 +167,16 @@ public class KnowledgeBaseInitService {
                 List<DocumentChunk> chunks = documentChunkService.chunkDocument(body, relativePath);
                 logger.debug("文档分块完成: {} -> {} 个 chunk", relativePath, chunks.size());
 
-                // 上传到 Milvus
+                // 上传到 Milvus hybrid collection（dense + BM25 search_text）
                 try {
-                    vectorIndexService.indexDocumentChunks(document.getDocId(), chunks, category);
+                    vectorIndexService.indexDocumentChunks(document.getDocId(), chunks, category, frontmatter);
 
                     document.setStatus("INDEXED");
                     document.setChunkCount(chunks.size());
                     document.setIndexedAt(LocalDateTime.now());
                     apiDocumentRepository.save(document);
 
-                    logger.info("文档已索引到 Milvus: {} (docId={}, chunks={})",
+                    logger.info("文档已索引到 Milvus hybrid: {} (docId={}, chunks={})",
                             title, document.getDocId(), chunks.size());
                 } catch (Exception e) {
                     logger.error("上传到 Milvus 失败: {}", relativePath, e);
@@ -161,6 +197,7 @@ public class KnowledgeBaseInitService {
                         .keywords(keywords)
                         .summary(summary)
                         .category(category)
+                        .kbScope(frontmatter.getKbScope())
                         .build();
                 knowledgeIndexService.addToIndex(entry);
 
@@ -344,4 +381,21 @@ public class KnowledgeBaseInitService {
         private long totalVectors;                // Milvus 中的向量总数
         private Map<String, Long> categoryCount;  // 按分类统计
     }
+
+    /**
+     * Full hybrid rebuild result.
+     */
+    @Data
+    public static class RebuildResult {
+        private boolean success;
+        private String basePath;
+        private String collection;
+        private long mysqlDocumentsBefore;
+        private long mysqlDocumentsAfterClear;
+        private long mysqlDocumentsAfterInit;
+        private int l0IndexSizeAfterClear;
+        private int l0IndexSizeAfterInit;
+        private Map<String, Object> milvus;
+        private InitResult init;
+    }
 }