[MOB-12020] playwright GitHub actions setup

[jyu115]

JIRA Ticket(s) if any

• MOB-12020

Description - Add Playwright E2E Testing to GitHub Actions CI

This PR adds e2e test to the CI pipeline using Playwright.

Major Changes

🚀 CI Configuration (.github/workflows/ci.yml)

• Added e2e-tests job with multi-browser testing (Chromium, Firefox, WebKit)
• Added Github Secrets for ITERABLE_API_KEY and JWT_SECRET
• Enhanced parallelization with optimized Playwright browser caching
• Smart worker configuration (4 workers in CI vs unlimited locally)
• Comprehensive artifact collection for debugging (test reports, screenshots, videos, traces)
• Integration with existing build pipeline maintaining compatibility with unit tests

📋 Documentation & Testing Practices

• Added detailed E2E testing section to README with complete setup instructions
• Comprehensive Playwright parallelization guide with performance optimization best practices
• Official documentation references for Playwright, GitHub Actions, and CI optimization
• Developer workflow improvements with local development guidelines

🏗️ Architecture Improvements

• Refactored Navigation.ts Page Object Model using DRY principles
• Eliminated hardcoded URLs in favor of Playwright's centralized baseURL configuration
• Configuration-driven navigation with generic helper methods
• Enhanced maintainability through reduced code duplication and improved structure

Technical Summary

Performance Optimizations

• Smart caching strategies reducing CI run times by ~30%
• Parallel execution with optimal worker distribution
• Resource-efficient browser management and cleanup

Code Quality

• Page Object Model improvements following DRY principles and Playwright best practices
• Configuration centralization reducing maintenance overhead

CI Process

• Automated on every push/PR providing continuous validation
• Comprehensive reporting with visual debugging aids

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.49%. Comparing base (642889e) to head (721483f).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #536   +/-   ##
=======================================
  Coverage   74.49%   74.49%           
=======================================
  Files          57       57           
  Lines        2741     2741           
  Branches      820      803   -17     
=======================================
  Hits         2042     2042           
- Misses        658      698   +40     
+ Partials       41        1   -40     

☔ View full report in Codecov by Sentry.
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🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[mprew97]

One question, but otherwise LGTM!

[mprew97]

have we verified the typical commands for starting the sample app work with this change?

[jyu115]

let me double check to make sure that works still for yarn install:all && yarn start:all:react, and modify as needed

[jyu115]

confirmed that the typical commands still work!