fix: declare tslib as a runtime dependency

[9renpoto]

Summary

• declare tslib@2.8.1 as a direct runtime dependency of all four published packages
• keep the version aligned with the official NestJS packages
• update the workspace lockfile

Why

The repository compiles with importHelpers: true, so the published JavaScript imports helpers from tslib at runtime. Relying on a transitive dependency makes the packages fail under strictly isolated dependency layouts such as pnpm.

Declaring tslib directly ensures each published package can resolve the helpers it emits without requiring consumers to install an undeclared implementation dependency.

Validation

• all four published package builds passed
• npm pack --dry-run passed for all four packages
• package manifests and workspace lockfile entries resolve tslib to 2.8.1
• git diff --check passed
• the root workspace build reaches the example app, which still fails with the existing TS5055 errors caused by files under example/dist

Closes #2019

This PR was prepared with OpenAI Codex.