feat: add reusable TypeScript and Node test workflows

[vitormattos]

Summary

Add reusable LibreCode implementations for two Nextcloud-derived workflows already used by LibreSign:

• lint-typescript.yml
• node-test.yml

Both are now tracked through the upstream pipeline:

nextcloud/.github -> immutable vendor source -> LibreCode patch -> reusable workflow

LibreCode adaptations include:

• replace Nextcloud-specific low-capacity runner labels with standard GitHub-hosted runners;
• expose the workflows through workflow_call;
• keep actions pinned to full commit SHAs;
• avoid expression interpolation directly inside shell conditionals;
• preserve the newer Codecov action already used by LibreSign for Node coverage.

No organization catalog templates are added yet. These implementations should first be exercised in a real LibreSign PR before publication.