Add a reference tab for LangSmith APIs and SDKs (#1574)

## Preview


https://langchain-5e9cc07a-preview-consol-1763754753-4714c41.mintlify.app/langsmith/reference

Author: katmayb

src/docs.json

@@ -867,23 +867,6 @@
                     "langsmith/user-management"
                   ]
                 },
-                {
-                  "group": "Reference",
-                  "pages": [
-                    "langsmith/smith-python-sdk",
-                    "langsmith/smith-js-ts-sdk",
-                    "langsmith/langgraph-python-sdk",
-                    "langsmith/langgraph-js-ts-sdk",
-                    "langsmith/smith-api-ref",
-                    {
-                      "group": "API reference for LangSmith Deployment",
-                      "pages": [
-                        "langsmith/server-api-ref",
-                        "langsmith/api-ref-control-plane"
-                      ]
-                    }
-                  ]
-                },
                 {
                   "group": "Additional resources",
                   "pages": [
@@ -1459,13 +1442,34 @@
                         "langsmith/script-running-ch-support-queries"
                       ]
                     }
-                    ]
-                  }
-                ]
-              }
-            ]
-          }
-        ]
+                  ]
+                }
+              ]
+            },
+            {
+              "tab": "Reference",
+              "pages": [
+                "langsmith/reference",
+                "langsmith/smith-python-sdk",
+                "langsmith/smith-js-ts-sdk",
+                "langsmith/langgraph-python-sdk",
+                "langsmith/langgraph-js-ts-sdk",
+                "langsmith/smith-api-ref",
+                {
+                  "group": "LangSmith Deployment",
+                  "pages": [
+                    "langsmith/server-api-ref",
+                    "langsmith/api-ref-control-plane",
+                    "langsmith/cli",
+                    "langsmith/remote-graph",
+                    "langsmith/env-var"
+                  ]
+                }
+              ]
+            }
+          ]
+        }
+      ]
   },
   "interaction": {
     "drilldown": true

src/langsmith/reference.mdx

@@ -0,0 +1,63 @@
+---
+title: LangSmith reference
+sidebarTitle: Overview
+mode: wide
+---
+
+The following sections provide API references and SDK documentation for LangSmith:
+
+<Columns cols={3}>
+  <Card
+    title="Python SDK"
+    icon="python"
+    href="/langsmith/smith-python-sdk"
+    arrow="true"
+  >
+    Reference documentation for the LangSmith Python SDK.
+  </Card>
+
+  <Card
+    title="JavaScript/TypeScript SDK"
+    icon="js"
+    href="/langsmith/smith-js-ts-sdk"
+    arrow="true"
+  >
+    Reference documentation for the LangSmith JavaScript/TypeScript SDK.
+  </Card>
+
+  <Card
+    title="LangGraph Python SDK"
+    icon="diagram-project"
+    href="/langsmith/langgraph-python-sdk"
+    arrow="true"
+  >
+    Reference documentation for deploying LangGraph applications with Python.
+  </Card>
+
+  <Card
+    title="LangGraph JS/TS SDK"
+    icon="diagram-project"
+    href="/langsmith/langgraph-js-ts-sdk"
+    arrow="true"
+  >
+    Reference documentation for deploying LangGraph applications with JavaScript/TypeScript.
+  </Card>
+
+  <Card
+    title="LangSmith API"
+    icon="code"
+    href="/langsmith/smith-api-ref"
+    arrow="true"
+  >
+    Complete REST API reference for LangSmith platform features.
+  </Card>
+
+  <Card
+    title="Deployment APIs"
+    icon="server"
+    href="/langsmith/server-api-ref"
+    arrow="true"
+  >
+    API references for self-hosted and hybrid LangSmith deployments.
+  </Card>
+</Columns>