feat(harness,rag): dual LLM audit fields, run conclusion, and hybrid quality

Persist provider reasoning and assistant text separately on agent_reasoning_audit
(DeepSeekAssistantMessage path), extract diagnosis_run.conclusion, enrich RAG
tool audit (step_id/query/qualityScore), gate empty mysql tools, drop devtools,
and align MVP docs after live E2E verification.

pom.xml

@@ -90,12 +90,12 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-devtools</artifactId>
-            <scope>runtime</scope>
-            <optional>true</optional>
-        </dependency>
+        <!--
+          spring-boot-devtools removed on purpose.
+          Classpath restart (restartedMain) recreates beans without reliably closing
+          MilvusClientV2 gRPC channels, causing orphan channels and long hybrid RPC retries.
+          Prefer full process restart: stop then `mvn spring-boot:run`.
+        -->
         <dependency>
             <groupId>io.milvus</groupId>
             <artifactId>milvus-sdk-java</artifactId>