Vite SSG + Vite+

### Describe the bug

[Vite SSG](https://github.com/antfu-collective/vite-ssg) and Vite+ is broken right now as the `includedRoutes` are not passed down with vite-plus.

```
file:///Users/shyim/Developer/shopmon/frontend/node_modules/vite-ssg/dist/shared/vite-ssg.D5Fdxh1E.mjs:1427
routesPaths = Array.from(new Set(routesPaths));
^

TypeError: object is not iterable (cannot read property Symbol(Symbol.iterator))
at new Set ()
at build (file:///Users/shyim/Developer/shopmon/frontend/node_modules/vite-ssg/dist/shared/vite-ssg.D5Fdxh1E.mjs:1427:28)
at async CAC. (file:///Users/shyim/Developer/shopmon/frontend/node_modules/vite-ssg/dist/node/cli.mjs:22:3)

Node.js v25.9.0
```

### Reproduction

https://github.com/antfu-collective/vite-ssg/tree/main/examples

### Steps to reproduce

- Clone [example](https://github.com/antfu-collective/vite-ssg/tree/main/examples)
- Convert to vite plus (vp migrate)
- Building crashes

### System Info

```shell
VITE+ - The Unified Toolchain for the Web

Environment:
Version 24.14.1
Source lts

Tool Paths:
node /Users/shyim/.vite-plus/js_runtime/node/24.14.1/bin/node
npm /Users/shyim/.vite-plus/js_runtime/node/24.14.1/bin/npm
npx /Users/shyim/.vite-plus/js_runtime/node/24.14.1/bin/npx
```

### Used Package Manager

npm

### Logs

```shell

```

### Validations

- [x] Read the [Contributing Guidelines](https://github.com/voidzero-dev/vite-plus/blob/main/CONTRIBUTING.md).
- [x] Check that there isn't [already an issue](https://github.com/voidzero-dev/vite-plus/issues) for the same bug.
- [x] Confirm this is a Vite+ issue and not an upstream issue (Vite, Vitest, tsdown, Rolldown, or Oxc).
- [x] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example).