fix(agent): clarify protocol capability contract

crates/dbx-core/assets/agent-protocol-v1.json

@@ -1,8 +1,39 @@
 {
   "protocolVersion": 1,
   "handshakeMethod": "handshake",
-  "handshakeResponseFields": ["protocolVersion", "agentProtocolVersion", "capabilities"],
-  "capabilities": ["connect", "test_connection", "metadata", "query", "paged_query", "transaction", "ddl", "kv"],
+  "handshakeResponseFields": [
+    "protocolVersion",
+    "agentProtocolVersion",
+    "capabilities"
+  ],
+  "allCapabilities": [
+    "connect",
+    "test_connection",
+    "metadata",
+    "query",
+    "paged_query",
+    "transaction",
+    "ddl",
+    "kv"
+  ],
+  "capabilities": [
+    "connect",
+    "test_connection",
+    "metadata",
+    "query",
+    "paged_query",
+    "transaction",
+    "ddl"
+  ],
+  "defaultSqlCapabilities": [
+    "connect",
+    "test_connection",
+    "metadata",
+    "query",
+    "paged_query",
+    "transaction",
+    "ddl"
+  ],
   "commonMethods": [
     "handshake",
     "connect",
@@ -26,6 +57,18 @@
     "disconnect",
     "shutdown"
   ],
-  "mongoLegacyMethods": ["list_databases", "list_collections", "find_documents", "insert_document", "update_document", "delete_document"],
-  "kvMethods": ["kv_list_prefix", "kv_get", "kv_put", "kv_delete"]
+  "mongoLegacyMethods": [
+    "list_databases",
+    "list_collections",
+    "find_documents",
+    "insert_document",
+    "update_document",
+    "delete_document"
+  ],
+  "kvMethods": [
+    "kv_list_prefix",
+    "kv_get",
+    "kv_put",
+    "kv_delete"
+  ]
 }