`vp` doesn't resolve `vite.config.ts` with `--conditions` flag

### Describe the bug

## I am doing

A package whose exports map has a `dev` condition pointing at TypeScript sources, and whose `vite.config.ts` imports the package by its own name (`@scope/thing/rules`). Running `vp lint` with the condition passed via `NODE_OPTIONS=--conditions=dev`, since `vp` has no `--conditions` flag of its own.

## What I expect

`vp` resolves `@scope/thing/rules` through the `dev` condition to `./src/rules.ts`, so the config loads from sources. Node resolves it that way with `--conditions=dev`, and `tsc` does with `customConditions: ["dev"]`.

## What is actually happening

The condition is ignored. Resolution falls through to default, `./dist/rules.js`. With no `dist/` built, that file doesn't exist, so the import is reported unresolved and marked external. Being external, it is then imported at runtime from `node_modules/.vite-temp/`, where Node's package scope lookup stops at the `node_modules` segment and the self-reference cannot resolve, so config loading fails outright.

It emits the following error

```log
$ NODE_OPTIONS=--conditions=dev vp lint
vite.config.ts (1:361) [UNRESOLVED_IMPORT] Could not resolve '@scope/thing/rules' in vite.config.ts
╭─[ vite.config.ts:1:362 ]
│
1 │ const __vite_injected_original_dirname = "$PWD/vite-plus-dev-config";const __vite_injected_original_filename = "$PWD/vite-plus-dev-config/vite.config.ts";const __vite_injected_original_import_meta_url = "file://$PWD/vite-plus-dev-config/vite.config.ts";import rules from "@scope/thing/rules";
│ ──────────┬─────────
│ ╰─────────── Module not found, treating it as an external dependency
───╯

failed to load config from $PWD/vite-plus-dev-config/vite.config.ts
[Vite+] resolve universal vite config error: Error [ERR_MODULE_NOT_FOUND]: Cannot find package '@scope/thing' imported from $PWD/vite-plus-dev-config/node_modules/.vite-temp/vite.config.ts.timestamp-1787978765772-966599996ab688.mjs
at Object.getPackageJSONURL (node:internal/modules/package_json_reader:301:9)
at packageResolve (node:internal/modules/esm/resolve:784:25)
at moduleResolve (node:internal/modules/esm/resolve:873:18)
at defaultResolve (node:internal/modules/esm/resolve:1006:11)
at #cachedDefaultResolve (node:internal/modules/esm/loader:708:20)
at #resolveAndMaybeBlockOnLoaderThread (node:internal/modules/esm/loader:728:38)
at ModuleLoader.resolveSync (node:internal/modules/esm/loader:766:56)
at #resolve (node:internal/modules/esm/loader:690:17)
at ModuleLoader.getOrCreateModuleJob (node:internal/modules/esm/loader:610:35)
at ModuleJob.syncLink (node:internal/modules/esm/module_job:277:33) {
code: 'ERR_MODULE_NOT_FOUND'
}
error: Failed to resolve vite config: GenericFailure, Cannot find package '@scope/thing' imported from $PWD/vite-plus-dev-config/node_modules/.vite-temp/vite.config.ts.timestamp-1787978765772-966599996ab688.mjs
error: script "lint" exited with code 1
```

Running bun run build first makes `dist/rules.js` exist and `vp lint` passes, which shows resolution itself works and only the condition is missing.

### Reproduction

https://github.com/ryansuhartanto/vite-plus-dev-config

### Steps to reproduce

```
$ bun install
$ bun run lint # Fail
$ bun run build
$ bun run lint # Now succeed
```

### System Info

```shell
Local vite-plus:
vite-plus v0.3.0

Tools:
vite v8.2.2
rolldown v1.2.5
vitest v4.1.11
oxfmt v0.64.0
oxlint v1.79.0
oxlint-tsgolint v7.0.2001
tsdown v0.22.14
```

### Used Package Manager

bun

### 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).

Use the linked reproduction and run `bun run lint` before and after `bun run build`; the failing entry point is `vp lint` with `NODE_OPTIONS=--conditions=dev`. Trace config loading and package resolution from `vite.config.ts`, then verify that the `dev` export condition resolves the TypeScript source without requiring `dist/` and that lint completes successfully.

Written by the indexing model from the issue text.