Updated all GitHub Actions workflows to use self-hosted runners instead of `ubuntu-latest`. This change ensures better control over the CI environment and aligns with internal infrastructure requirements.
- Introduced `run-vitest-unit-batches.mjs` script for running unit tests in batches with configurable batch size.
- Updated `package.json` to replace `test:unit` command with the batch runner and added `test:unit:single` for direct execution.
- Tweaked GitHub workflows (`tests.yml`, `code_quality.yml`) to use updated actions and support batch testing.
- Minor formatting improvements in Vue components and workflows for consistent style.