fix(plugin): preserve package import paths

[yudin-s]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

When the CLI plugin sees a DTO property typed from a workspace package import such as @repro/shared/messages, TypeScript may resolve the type to the package physical output path. The generated _OPENAPI_METADATA_FACTORY() can then emit a filesystem-relative require() into packages/shared/dist/..., which is not stable at runtime after the package is installed from node_modules.

Issue Number: Fixes #3937

What is the new behavior?

The model visitor now preserves explicit package import specifiers for imported property/enum types before normalizing paths. Package-style references keep emitting package-based require() calls, while relative and built-in/bare module behavior stays unchanged.

A regression fixture covers a monorepo-style DTO importing an enum from @repro/shared/messages and asserts the emitted metadata uses require("@repro/shared/messages").ItemStatus instead of a resolved sibling package path.

Does this PR introduce a breaking change?

• Yes
• No

Other information

Docs were not updated because this is a CLI plugin code-generation bug fix with regression coverage.

Local validation:

npm test -- test/plugin/plugin-utils.spec.ts test/plugin/model-class-visitor.spec.ts
npm test -- test/plugin
npm run build -- --pretty false
npm exec -- prettier --check lib/plugin/utils/plugin-utils.ts lib/plugin/visitors/model-class.visitor.ts test/plugin/plugin-utils.spec.ts test/plugin/model-class-visitor.spec.ts test/plugin/fixtures/package-imports/apps/api/src/item.dto.ts test/plugin/fixtures/package-imports/packages/shared/dist/messages/item.d.ts test/plugin/fixtures/package-imports/tsconfig.json
npm run lint
git diff --check

Note: local install required restoring optional native packages for Vitest/oxlint on macOS; no package manifest or lockfile changes are included.

[SmallhillCZ]

whoah! hoped this would be simpler :) thanks for working on this!

[SmallhillCZ]

@yudin-s @kamilmysliwiec hi, is there an ETA for merging? thanks