Fix Windows libuv abort in concept-seed after a successful roll (#526)

* Fix Windows libuv abort in concept-seed after a successful roll

process.exit() with a live fetch keep-alive socket trips libuv's
UV_HANDLE_CLOSING assertion on Windows (nodejs/node#56645), aborting
the CLI with 0xC0000409 after complete output on the successful-roll
path. Destroy the global undici dispatcher before the explicit exit
so no socket is left to race; the hard exit stays, keeping the
no-linger guarantee on blackholed networks.

Fixes #504

Prepared with AI assistance (Cursor agent) under maintainer direction.

* Add regression test for the successful-API dispatcher teardown

The suite covered local rolls and the unreachable-API fallback but
never a successful roll, the one path where a pooled keep-alive
socket exists at exit (issue #504). Serve a real /api/roll from a
local server and assert the CLI destroys fetch's global dispatcher
before its explicit exit. Verified to fail without the fix.

Prepared with AI assistance (Cursor agent) under maintainer direction.

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

skill/scripts/concept-seed.mjs

@@ -692,6 +692,13 @@ if (process.argv[1] && resolve(process.argv[1]) === fileURLToPath(import.meta.ur
     process.exitCode = 1;
   }
   // A raced-out fetch may still hold a socket; exit explicitly so the CLI
-  // never lingers on a dead network path after output is written.
+  // never lingers on a dead network path after output is written. Destroy
+  // fetch's global undici dispatcher first: process.exit() with a live
+  // keep-alive socket trips a libuv assertion on Windows and aborts the
+  // process after a successful roll (nodejs/node#56645).
+  const dispatcher = globalThis[Symbol.for('undici.globalDispatcher.1')];
+  if (dispatcher && typeof dispatcher.destroy === 'function') {
+    try { await dispatcher.destroy(); } catch { /* exit regardless */ }
+  }
   process.exit(process.exitCode ?? 0);
 }