docs: vcr only set up for markdown (#3339)

- PR branch for testing w/ typescript (@benjamincburns )
- implementation needs better cache invalidation for the cassettes
(@eyurtsev)

---------

Co-authored-by: Ben Burns <803016+benjamincburns@users.noreply.github.com>

docs/package.json

@@ -4,5 +4,17 @@
   "license": "MIT",
   "scripts": {
     "build": "echo 'export PATH=$PATH:/vercel/.local/bin:$PATH' > ~/.bashrc && source ~/.bashrc && make vercel-build-docs"
+  },
+  "dependencies": {
+    "@langchain/core": "^0.3.38",
+    "@langchain/openai": "^0.4.2",
+    "msgpack-lite": "^0.1.26",
+    "nock": "^14.0.1"
+  },
+  "devDependencies": {
+    "@tsconfig/recommended": "^1.0.8",
+    "@types/msgpack-lite": "^0.1.11",
+    "@types/nock": "^11.1.0",
+    "@types/node": "^22.13.1"
   }
 }