`vp dev`& `vp build` break argv passthrough by stripping the `--` separator

### Describe the bug

Every `vp` CLI layer consumes one `--` argument separator, so passthrough args that Vite leaves in `process.argv` for `vite.config.ts` to read never arrive. Actually the flags after the stripped `--` even get misparsed as Vite positionals.

With plain Vite, `vite build -- --app web` keeps `--app web` out of option parsing and visible in `process.argv` (often sude to parameterize a single hoisted config in a monorepo).

But in `vp` this is broken:

| Command | Result |
| --- | --- |
| `vp build -- --app web` | broken: `--` stripped, Vite parses `--app web`, **`web` becomes the build root** (`Cannot resolve entry module web/index.html`), the project config never loads |
| `vp build -- -- --app web` | still broken: second `--` stripped too |
| `vp build -- -- -- --app web` | works: config sees `ARGV=["build","--","--app","web"]` |

So global `vp` needs three `--` where Vite needs one, and a project-local `vp` needs two.

Expected: `vp dev -- --app` / `vp build -- --app` behave exactly like `vite dev -- --app` — one `--`, trailing args preserved in the spawned Vite process's `process.argv`.

### Reproduction

See steps below (three files, no dependencies).

### Steps to reproduce

```bash
mkdir repro && cd repro
cat > package.json <<'PKG'
{ "name": "repro", "private": true, "type": "module" }
PKG
cat > vite.config.ts <<'CFG'
console.log('ARGV=' + JSON.stringify(process.argv.slice(2)));
export default {};
CFG
cat > index.html <<'HTML'
hi
HTML

vp build -- --app web # fails: Cannot resolve entry module web/index.html, no ARGV log
vp build -- -- -- --app web # works: ARGV=["build","--","--app","web"]
```

### System Info

```shell
vp v0.2.2 (global), macOS (Darwin 25.5.0)
Also reproducible on main
```

### Used Package Manager

pnpm

### Logs

### 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).