feat: 收敛知识库检索调度与评分语义

- 固定 rag.engine 与 Milvus 配置，补齐启动期检索基础设施校验

- 支持调用方配置 retrievalMode，并统一知识库检索入口与结果来源展示

- 修正关键词检索 knowledgeId 过滤、混合检索评分归一化与本地 ES 默认配置

easyflow-starter/easyflow-starter-all/src/main/resources/application.yml

@@ -208,12 +208,19 @@ jetcache:
 
 # 多路召回搜索引擎配置
 rag:
+  engine: ES
+  milvus:
+    uri: http://127.0.0.1:39530
+    databaseName: default
+    token:
+    username: easyflowadmin
+    password: easyflowadmin123
+    autoCreateCollection: true
   searcher:
-    # 搜索方式 默认lucene
     lucene:
       indexDirPath: /Users/slience/data/easyflow/luceneKnowledge
     elastic:
-      host: https://127.0.0.1:9200
+      host: http://127.0.0.1:39200
       userName: elastic
       password: elastic
       indexName: easyflow