[EPIC] Improve times on CI/CD and Quality

Task

As a Frontend Developer, I want a modern, fast, and reliable development environment with clear coding standards, so that I can build high-quality features faster, with fewer bugs, and a delivery value quickly

Proposed Objective

• [ ] Performance: CI/CD pipeline execution time is demonstrably reduced due to build and test optimizations (Vite, Vitest).
• [ ] Velocity: The development feedback loop is faster thanks to a modernized stack and tooling (e.g., Vite HMR).
• [ ] Modernization: The entire frontend platform is running on Angular v20+ and Nx v21+.
• [ ] Quality: A comprehensive style guide is adopted and enforced through automated linting and formatting. strict mode is enabled across all projects.
• [ ] Code Health: The codebase is fully migrated to modern Angular patterns, including Standalone components, Signals, and the inject function.
• [ ] Reliability: The testing strategy is successfully migrated to Vitest for unit tests and Playwright for E2E tests, increasing confidence in releases.
• [ ] Maintainability: All identified deprecated libraries and internal services have been removed or migrated to their modern replacements

Start by reviewing the epic objectives and the linked pull request #35155, then identify the separate work needed for Angular, Nx, Vite, Vitest, Playwright, linting, formatting, strict mode, and modern Angular patterns. Done requires the listed CI/CD, modernization, quality, code-health, testing, and deprecation-removal goals to be demonstrably complete.