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/_scripts/assets/nock_setup_preamble.ts

@@ -0,0 +1,75 @@
+import nock, { Definition } from "nock";
+import msgpack from "msgpack-lite";
+import zlib from "node:zlib";
+import fs from "node:fs/promises";
+import { Buffer } from "node:buffer";
+
+// deno style imports here because we're running this in the deno jupyter kernel
+
+interface NockCassetteData {
+  hash: string;
+  entries: Definition[];
+}
+
+// Utility functions for compression & serialization
+function compressData(data: NockCassetteData, compressionLevel = 9): string {
+  const packed = msgpack.encode(data);
+  const compressed = zlib.deflateSync(packed, { level: compressionLevel });
+  return compressed.toString("base64");
+}
+
+function decompressData(compressedString: string): NockCassetteData {
+  const decoded = Buffer.from(compressedString, "base64");
+  const decompressed = zlib.inflateSync(decoded);
+  return msgpack.decode(decompressed) as NockCassetteData;
+}
+
+// deno-lint-ignore no-unused-vars
+class HashedCassette {
+  private recording = true;
+
+  constructor(
+    private readonly cassettePath: string,
+    private readonly hash: string
+  ) {}
+
+  async enter() {
+    try {
+      const rawCassette = await fs.readFile(this.cassettePath, "utf-8");
+      const data = decompressData(rawCassette);
+      if (data.hash === this.hash) {
+        this.recording = false;
+        nock.disableNetConnect();
+        nock.define(data.entries);
+        return;
+      }
+    } catch (error) {
+      if (error instanceof Error && error.message.includes("ENOENT")) {
+        this.recording = true;
+      } else {
+        throw error;
+      }
+    }
+
+    nock.recorder.rec({
+      dont_print: true,
+      output_objects: true,
+    });
+  }
+
+  async exit() {
+    if (this.recording) {
+      const entries = nock.recorder.play() as Definition[];
+      const data = {
+        hash: this.hash,
+        entries,
+      };
+      const compressed = compressData(data);
+      await fs.writeFile(this.cassettePath, compressed);
+    } else {
+      nock.enableNetConnect();
+      nock.restore();
+      nock.cleanAll();
+    }
+  }
+}