feat(03-07): add LangSmith and 6 vector DB providers

- LangSmith with lsv2_(pt|sk) high-confidence regex
- Pinecone with pcsk_ high-confidence regex
- Weaviate, Qdrant, Chroma, Milvus/Zilliz, Neon (keyword-only)
- Completes 15 Tier 6 emerging/niche providers (PROV-06)

providers/milvus.yaml

@@ -0,0 +1,18 @@
+format_version: 1
+name: milvus
+display_name: Milvus / Zilliz
+tier: 6
+last_verified: "2026-04-05"
+keywords:
+  - "milvus"
+  - "zilliz"
+  - "ZILLIZ_API_KEY"
+  - "MILVUS_TOKEN"
+  - "zilliz.com"
+  - "api.cloud.zilliz.com"
+verify:
+  method: GET
+  url: ""
+  headers: {}
+  valid_status: []
+  invalid_status: []