fix: keep fetch on HTTP/1.1 so Node 26 does not exit the wizard mid-run

bin.ts

@@ -1,5 +1,6 @@
 #!/usr/bin/env node
 import { satisfies } from 'semver';
+import { Agent, setGlobalDispatcher } from 'undici';
 import { ErrorCodes } from './src/lib/errors/codes.js';
 import { emitWizardError } from './src/lib/errors/emit.js';
 
@@ -9,6 +10,19 @@ import { emitWizardError } from './src/lib/errors/emit.js';
 // TypeError on Node < 22.10).
 const NODE_VERSION_RANGE = '>=22.22.0';
 
+/*
+ * TODO(#1198): remove when fetch over HTTP/2 is safe on Node 26. Remove when all
+ * of these are true:
+ *  - nodejs/node no longer creates an orphan ClientHttp2Stream when a client
+ *    session gets HEADERS for a stream id it already reset. Repro: abort a fetch
+ *    before its response headers, then idle 4s on Node 26. Fixed when the
+ *    process survives.
+ *  - modelcontextprotocol/typescript-sdk#2526 is closed.
+ *  - pi-coding-agent's CLI drops `allowH2: false` from its http-dispatcher.
+ * Same workaround as pi's CLI and typescript-sdk#2526: HTTP/1.1 only.
+ */
+setGlobalDispatcher(new Agent({ allowH2: false }));
+
 // Have to run this above the other imports because they are importing clack that
 // has the problematic imports.
 if (!satisfies(process.version, NODE_VERSION_RANGE)) {

package.json

@@ -60,6 +60,7 @@
     "recast": "^0.23.3",
     "semver": "^7.5.3",
     "typebox": "1.1.38",
+    "undici": "8.5.0",
     "uuid": "^11.1.0",
     "xcode": "3.0.1",
     "xml-js": "^1.6.11",