chore: require Node >=25 and pnpm >=11.3 (#12459)

## Summary

Bump required Node.js to `>=25` and pnpm to `>=11.3`.

## Changes

- **What**: Updated `engines.node` to `>=25`, `engines.pnpm` to
`>=11.3`, and `packageManager` to `pnpm@11.3.0` in `package.json`.
Bumped `.nvmrc` from `24` to `25`.
- **Breaking**: Contributors and CI must now use Node 25+ and pnpm
11.3+.

## Review Focus

CI workflows resolve Node from `.nvmrc`, so they pick up the bump
automatically. Confirm no downstream tooling pins an older Node/pnpm.

---------

Co-authored-by: Amp <amp@ampcode.com>

.nvmrc

@@ -1 +1 @@
-24
+25

package.json

@@ -206,8 +206,8 @@
     "zod-to-json-schema": "catalog:"
   },
   "engines": {
-    "node": "24.x",
-    "pnpm": ">=11"
+    "node": ">=25",
+    "pnpm": ">=11.3"
   },
-  "packageManager": "pnpm@11.1.1"
+  "packageManager": "pnpm@11.3.0"
 }

vite.config.mts

@@ -651,6 +651,13 @@ export default defineConfig({
   test: {
     globals: true,
     environment: 'happy-dom',
+    // Node 25+ enables the Web Storage API by default, which shadows
+    // happy-dom's localStorage/sessionStorage with a non-functional Proxy.
+    // See https://github.com/capricorn86/happy-dom/issues/1950
+    execArgv:
+      Number(process.versions.node.split('.')[0]) >= 25
+        ? ['--no-experimental-webstorage']
+        : [],
     setupFiles: ['./vitest.setup.ts'],
     retry: process.env.CI ? 2 : 0,
     include: [