Add Playwright E2E testing framework, CI step, and scripts for full p…

[martinshub-tech]

this pr closes #61

Summary

This PR introduces the Playwright end‑to‑end (E2E) testing framework to the Quantara platform and integrates it into the CI pipeline. It satisfies the first phase of setting up the testing environment for the complete position lifecycle.

What’s Included

• Playwright Configuration (frontend/playwright.config.js): Setup for Chromium, headless mode, timeouts, retries, and HTML reporting.
• Dependency Integration: Added @playwright/test to devDependencies in frontend/package.json (installed using --legacy-peer-deps to bypass ESLint version conflicts).
• Test Scripts: Added "e2e": "playwright test" to the package scripts.
• CI Workflow Integration (.github/workflows/frontend_tests.yml): Integrated the E2E test suite running step (yarn e2e) directly into the automated frontend testing pipeline.
• Test Directory: Created the frontend/test/e2e directory structure.

Verification

• Dependencies successfully installed.
• Local repository clean and all changes committed to the add-e2e-playwright branch.

[YaronZaki]

Cool direction — Playwright will be a big win for us. But CI is red on the test job right now, please take a look at the failure and get it green before we merge.