chore(rag): rebuild script in Python and use biz collection

Switch default knowledge collection back to biz (drop+recreate on rebuild),
replace PowerShell rebuild runner with Python, skip README.md imports, and
merge duplicate rag keys in application.yml.

src/main/java/com/superbiz/agent/constant/MilvusConstants.java

@@ -8,14 +8,15 @@ public class MilvusConstants {
     public static final String MILVUS_DB_NAME = "default";
     
     /**
-     * Legacy collection name (pre hybrid). Knowledge path uses milvus.collection (default biz_hybrid).
+     * Default knowledge collection name (dense + BM25).
+     * Overridable via {@code milvus.collection}.
      */
     public static final String MILVUS_COLLECTION_NAME = "biz";
 
     /**
-     * Default hybrid dense+BM25 collection.
+     * Alias kept for readability in hybrid-related code.
      */
-    public static final String MILVUS_HYBRID_COLLECTION_NAME = "biz_hybrid";
+    public static final String MILVUS_HYBRID_COLLECTION_NAME = MILVUS_COLLECTION_NAME;
     
     /**
      * 向量维度（豆包 embedding 模型的维度）

src/main/java/com/superbiz/agent/controller/KnowledgeBaseController.java

@@ -67,7 +67,7 @@ public class KnowledgeBaseController {
      * 清空 hybrid collection + MySQL api_document + L0 内存索引，
      * 再从 knowledge_base 全量重建 dense+BM25 索引。
      *
-     * <p>危险操作：会删除 {@code milvus.collection}（默认 biz_hybrid）与文档元数据表数据。
+     * <p>危险操作：会删除 {@code milvus.collection}（默认 {@code biz}）与文档元数据表数据。
      * 需要显式 confirm=REBUILD。</p>
      */
     @PostMapping("/rebuild-hybrid")

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

@@ -57,7 +57,7 @@ public class KnowledgeBaseInitService {
 
     /**
      * Drop hybrid collection, clear MySQL api_document + L0 memory index,
-     * then force-import all markdown under knowledge.base-path into biz_hybrid.
+     * then force-import all markdown under knowledge.base-path into milvus.collection (default biz).
      */
     @Transactional(rollbackFor = Exception.class)
     public RebuildResult rebuildHybridFromKnowledgeBase() {
@@ -82,6 +82,8 @@ public class KnowledgeBaseInitService {
         rebuild.setInit(init);
         rebuild.setL0IndexSizeAfterInit(knowledgeIndexService.getIndexSize());
         rebuild.setMysqlDocumentsAfterInit(apiDocumentRepository.count());
+        // Success when at least one doc indexed and no hard failures.
+        // README-like docs are skipped by scanner; remaining failures still mark unsuccessful.
         rebuild.setSuccess(init.getFailed() == 0 && init.getInserted() > 0);
         logger.info("Hybrid knowledge rebuild finished: success={}, inserted={}, failed={}",
                 rebuild.isSuccess(), init.getInserted(), init.getFailed());
@@ -257,7 +259,11 @@ public class KnowledgeBaseInitService {
             Files.walkFileTree(baseDir, new SimpleFileVisitor<Path>() {
                 @Override
                 public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
-                    if (file.toString().endsWith(".md")) {
+                    String name = file.getFileName() == null ? "" : file.getFileName().toString();
+                    // Import content docs only; skip README/index markdown without frontmatter.
+                    if (name.endsWith(".md")
+                            && !name.equalsIgnoreCase("README.md")
+                            && !name.equalsIgnoreCase("readme.md")) {
                         files.add(file);
                     }
                     return FileVisitResult.CONTINUE;

src/main/java/com/superbiz/agent/service/milvus/MilvusHybridKnowledgeStore.java

@@ -61,8 +61,8 @@ public class MilvusHybridKnowledgeStore {
 
     private final MilvusProperties milvusProperties;
 
-    @Value("${milvus.collection:biz_hybrid}")
-    private String collectionName = "biz_hybrid";
+    @Value("${milvus.collection:biz}")
+    private String collectionName = "biz";
 
     @Value("${retrieval.hybrid.rrf-k:60}")
     private int rrfK = 60;
@@ -144,8 +144,8 @@ public class MilvusHybridKnowledgeStore {
     }
 
     /**
-     * Drop the hybrid collection (if present) and recreate empty dense+BM25 schema.
-     * Used by knowledge rebuild scripts. Does not touch legacy {@code biz} collection.
+     * Drop the configured knowledge collection (if present) and recreate empty dense+BM25 schema.
+     * Used by knowledge rebuild scripts. Existing vectors in this collection are destroyed.
      */
     public synchronized Map<String, Object> dropAndRecreateCollection() {
         Map<String, Object> result = new LinkedHashMap<>();