docs(pack): suggest vp env use 26 for the exe SEA build

Node 26 is the version the exe targets default to and clears the 25.7
SEA floor; `vp env use 25` could resolve below it.

Author: fengmk2

docs/guide/pack.md

@@ -60,7 +60,7 @@ export default defineConfig({
 
 Executable support is bundled into Vite+, so you do not need to install `@tsdown/exe` separately.
 
-Building executables uses Node's [Single Executable Applications](https://nodejs.org/api/single-executable-applications.html) support and requires Node.js 25.7.0 or later. Switch the active runtime with `vp env use 25` if `vp pack --exe` reports an unsupported version.
+Building executables uses Node's [Single Executable Applications](https://nodejs.org/api/single-executable-applications.html) support and requires Node.js 25.7.0 or later. Switch the active runtime with `vp env use 26` if `vp pack --exe` reports an unsupported version.
 
 See the official [tsdown executable docs](https://tsdown.dev/options/exe#executable) for details about configuring custom file names, embedded assets, and cross-platform targets.