feat(nodes): add feature-flag-gated --enable-infiniband to sf nodes create

The option is only mounted when the user's account has the
`infiniband-preview` flag enabled (checked via the existing posthog/
feature-flag helper). When enabled, it shows up in `sf nodes create --help`
and forwards `_preview_enable_infiniband: true` to the nodes SDK, exposing
the InfiniBand preview surface in the sfcompute/sfcompute API.

Generated with [Indent](https://indent.com)
Co-Authored-By: Indent <noreply@indent.com>

Author: sigmachirality

src/lib/nodes/create.ts

@@ -56,6 +56,17 @@ function formatNodeDescription(
  * @returns Parsed count value
  * @throws CommanderError if invalid
  */
+/**
+ * Opt-in flag for InfiniBand-backed nodes. Gated behind the `infiniband-preview`
+ * feature flag in `registerNodes`, so it is only added to `sf nodes create` for
+ * accounts the server-side allowlist permits. The wire field is still in preview
+ * (named `_preview_enable_infiniband`), so the option may change without notice.
+ */
+export const enableInfinibandOption = new Option(
+  "--enable-infiniband",
+  "Enable InfiniBand on the nodes (preview).",
+);
+
 function validateCount(val: string): number {
   const parsed = Number.parseInt(val, 10);
   if (Number.isNaN(parsed) || parsed <= 0) {
@@ -240,7 +251,10 @@ Examples:\n
 
 async function createNodesAction(
   names: typeof create.args,
-  options: ReturnType<typeof create.opts> & { image?: string },
+  options: ReturnType<typeof create.opts> & {
+    image?: string;
+    enableInfiniband?: boolean;
+  },
 ) {
   try {
     const client = await nodesClient();
@@ -274,6 +288,7 @@ async function createNodesAction(
       cloud_init_user_data: encodedUserData,
       image_id: options.image,
       node_type: isReserved ? "reserved" : "autoreserved",
+      ...(options.enableInfiniband ? { _preview_enable_infiniband: true } : {}),
     };
 
     if (isReserved) {

src/lib/nodes/index.ts

@@ -1,7 +1,8 @@
 import console from "node:console";
 import type { Command } from "@commander-js/extra-typings";
 
-import create from "./create.ts";
+import { isFeatureEnabled } from "../posthog.ts";
+import create, { enableInfinibandOption } from "./create.ts";
 import deleteCommand from "./delete.ts";
 import extend from "./extend.ts";
 import get from "./get.tsx";
@@ -13,7 +14,11 @@ import release from "./release.ts";
 import set from "./set.ts";
 import ssh from "./ssh.ts";
 
-export function registerNodes(program: Command) {
+export async function registerNodes(program: Command) {
+  if (await isFeatureEnabled("infiniband-preview")) {
+    create.addOption(enableInfinibandOption);
+  }
+
   const nodes = program
     .command("nodes")
     .alias("node")

src/lib/posthog.ts

@@ -62,7 +62,7 @@ const trackEvent = ({
   }
 };
 
-type FeatureFlags = "procurements" | "zones";
+type FeatureFlags = "procurements" | "zones" | "infiniband-preview";
 
 /**
  * Checks if a feature is enabled for the current user.