feat(rag): dense+BM25 hybrid on MilvusClientV2, drop SDK path

Replace legacy MilvusServiceClient knowledge search/write with a single MilvusClientV2 hybrid store (BM25 function + dense ANN + RRFRanker). Use collection biz_hybrid and require knowledge reindex.
2026-07-27 18:49:20 +08:00
parent 376ad0c241
commit f035538531
22 changed files with 813 additions and 936 deletions
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+# Decisions
+
+- Single backend: MilvusClientV2 only for knowledge RAG
+- Drop sdk/spring/auto retrieval routing
+- New collection biz_hybrid to avoid mutating legacy biz schema in place
+- Hybrid = dense ANN + BM25 sparse ANN + RRFRanker
+- Dense L2 enrichment for threshold compatibility on hybrid hits