cherry-pick: fix(docs): use label-based API version mapping in v4.2.0 aztec-nr api page (with conflicts)

Mechanical cherry-pick of 0e1c474 from PR #22617. The original fix
targets docs/developer_versioned_docs/version-v4.2.0/docs/aztec-nr/api.mdx,
which does not exist on v4-next. Git's rename detection landed the diff on
docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/aztec-nr/api.mdx,
producing conflict markers. Committed AS-IS for history; next commit
reverts the wrong target and applies the fix to the right file on v4-next.

Author: critesjosh

docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/aztec-nr/api.mdx

@@ -10,6 +10,7 @@ import { useActiveVersion } from "@docusaurus/plugin-content-docs/client";
 
 export const useApiVersion = () => {
   const version = useActiveVersion("developer");
+<<<<<<< HEAD:docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/aztec-nr/api.mdx
   const versionName = version?.name || "current";
   // Map Docusaurus version to API docs folder
   // Use stable paths for nightly/devnet, version-specific for others
@@ -18,6 +19,15 @@ export const useApiVersion = () => {
   if (versionName.includes("devnet")) return "devnet";
   if (versionName.includes("rc") || versionName.includes("testnet")) return "testnet";
   return versionName;
+=======
+  if (!version || version.name === "current") return "next";
+  // Map Docusaurus version to API docs folder using version label
+  // Labels are set explicitly in docusaurus.config.js (e.g., "Mainnet (...)")
+  const label = version.label || "";
+  if (label.startsWith("Alpha")) return "mainnet";
+  if (label.startsWith("Testnet")) return "testnet";
+  return version.name;
+>>>>>>> 0e1c4740b2 (fix(docs): use label-based API version mapping in v4.2.0 aztec-nr api page):docs/developer_versioned_docs/version-v4.2.0/docs/aztec-nr/api.mdx
 };
 
 export const ModuleLink = ({ path, children }) => {