fix(build): patch payload loadEnv for OpenNext's @next/env shim

OpenNext worker bundling (esbuild) failed with:
  No matching export in shims/env.js for import "default"  (payload/dist/bin/loadEnv.js)
loadEnv does `import x from '@next/env'` (a default import — correct for the real
CJS package), but OpenNext replaces @next/env with an ESM shim exposing only a
named `loadEnvConfig` (no default). loadEnv is pulled into the worker bundle via
payload/node yet never runs at worker runtime. pnpm-patch it to a namespace import
with a default fallback (`nextEnvImport.loadEnvConfig ?? nextEnvImport.default?.
loadEnvConfig`), which resolves against both the ESM shim and the real CJS package.

With this, the full `opennextjs-cloudflare build` completes locally against the real
D1/R2 (remote bindings) — .open-next/worker.js saved. Remove this patch once the
Payload/OpenNext @next/env interop is fixed upstream.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ceccec

package.json

@@ -169,6 +169,9 @@
     "overrides": {
       "formdata-node": "6.0.3",
       "preact": ">=10.28.2"
+    },
+    "patchedDependencies": {
+      "payload@4.0.0-canary.1": "patches/payload@4.0.0-canary.1.patch"
     }
   },
   "packageManager": "pnpm@10.33.2",

patches/payload@4.0.0-canary.1.patch

@@ -0,0 +1,13 @@
+diff --git a/dist/bin/loadEnv.js b/dist/bin/loadEnv.js
+index b61ecc1684f0b686fa8bbcefa68b5ed825c09420..a7eca40e1d7ca727cb103fdb26361139b8113e2d 100644
+--- a/dist/bin/loadEnv.js
++++ b/dist/bin/loadEnv.js
+@@ -1,6 +1,6 @@
+-import nextEnvImport from '@next/env';
++import * as nextEnvImport from '@next/env';
+ import { findUpSync } from '../utilities/findUp.js';
+-const { loadEnvConfig } = nextEnvImport;
++const loadEnvConfig = nextEnvImport.loadEnvConfig ?? nextEnvImport.default?.loadEnvConfig;
+ /**
+  * Try to find user's env files and load it. Uses the same algorithm next.js uses to parse env files, meaning this also supports .env.local, .env.development, .env.production, etc.
+  */ export function loadEnv(path) {