blitzjs app router doesn't support vercel deploy

### What is the problem?

after this https://github.com/gengjiawen/sass-template/commit/e3dbfc04fba523213404f4a14845e7631a99e11f

### Paste all your error logs here:

```
⨯ Error: Usage of `getBlitzContext` is supported only in next.js 13.0.0 and above. Please upgrade your next.js version.
at (.next/server/chunks/881.js:77:23128)
at Generator.next ()
at (.next/server/chunks/881.js:77:20730)
at new Promise ()
at ej (.next/server/chunks/881.js:77:20550)
at eD (.next/server/chunks/881.js:77:22851)
at (.next/server/chunks/881.js:3:4990)
at Generator.next ()
at (.next/server/chunks/881.js:3:4875)
at new Promise () {
digest: '744844193'
}```

### Paste all relevant code snippets here:

```
PASTE_HERE (leave the ``` marks)
```

### What are detailed steps to reproduce this?

1.

### Run `blitz -v` and paste the output here:

```
System:
OS: Linux 6.1 Ubuntu 22.04.5 LTS 22.04.5 LTS (Jammy Jellyfish)
CPU: (16) x64 AMD EPYC 7B13
Memory: 35.83 GB / 62.79 GB
Shell: 5.1.16 - /bin/bash
Binaries:
Node: 22.13.1 - ~/.nvm/versions/node/v22.13.1/bin/node
Yarn: 1.22.22 - ~/.nvm/versions/node/v22.13.1/bin/yarn
npm: 10.9.2 - ~/.nvm/versions/node/v22.13.1/bin/npm
npmPackages:
@blitzjs/auth: 3.0.1 => 3.0.1
@blitzjs/next: 3.0.1 => 3.0.1
@blitzjs/rpc: 3.0.1 => 3.0.1
@prisma/client: 6.5.0 => 6.5.0
blitz: 3.0.1 => 3.0.1
next: 15.2.2 => 15.2.2
prisma: 6.5.0 => 6.5.0
react: 19.0.0 => 19.0.0
react-dom: 19.0.0 => 19.0.0
typescript: 5 => 5.8.2 ```

### Please include below any other applicable logs and screenshots that show your problem:

_No response_