Fix CircleCI JUnit XML test result collection

Summary

Resolves the CircleCI "0 test results uploaded" issue by fixing JUnit XML generation problems in both unit and E2E test configurations. The root causes were:

1. Missing script reference: playwright.config.test.ts referenced npm run serve which doesn't exist in package.json (should be npm start)
2. File conflicts: Both Karma unit tests and Playwright E2E tests were writing to the same test-results/junit.xml file
3. Configuration gaps: Missing karma-junit-reporter dependency and incomplete CircleCI browser orb usage

Key Changes:

• Fixed Playwright webServer command to use existing npm start script
• Separated JUnit XML outputs: junit.xml (unit tests) and e2e-junit.xml (E2E tests)
• Added karma-junit-reporter dependency and configured Karma to output JUnit XML
• Updated CircleCI to use Node.js v20.19 and proper browser-tools orb usage

Review & Testing Checklist for Human

• Verify CircleCI shows test results uploaded instead of "0 test results uploaded" message
• Test npm start command works correctly and serves the app on localhost:4200
• Check CI logs to confirm both test-results/junit.xml and test-results/e2e-junit.xml files are generated
• Run unit tests locally with npm run test:unit and verify test-results/junit.xml is created (should be ~75KB)
• Test E2E configuration with npx playwright test --config=playwright.config.test.ts --list to confirm no script errors

Recommended Test Plan: Run the CircleCI pipeline and check the "Test Summary" tab to verify test results are properly uploaded and displayed, rather than showing "0 test results uploaded".

Diagram

%%{ init : { "theme" : "default" }}%%
graph TD
    subgraph "Test Configuration Files"
        A["playwright.config.test.ts"]:::major-edit
        B["karma.conf.js"]:::minor-edit
        C["package.json"]:::minor-edit
    end
    
    subgraph "CircleCI Pipeline"
        D[".circleci/config.yml"]:::context
        E["unit-tests job"]:::context
        F["e2e-tests job"]:::context
    end
    
    subgraph "Test Results"
        G["test-results/junit.xml<br/>(Unit Tests)"]:::context
        H["test-results/e2e-junit.xml<br/>(E2E Tests)"]:::context
    end
    
    A -->|"webServer: npm start"| E
    A -->|"junit reporter"| H
    B -->|"junit reporter"| G
    C -->|"karma-junit-reporter"| B
    E -->|"store_test_results"| G
    F -->|"store_test_results"| H
    D -->|"configures"| E
    D -->|"configures"| F
    
    subgraph Legend
        L1["Major Edit"]:::major-edit
        L2["Minor Edit"]:::minor-edit
        L3["Context/No Edit"]:::context
    end

classDef major-edit fill:#90EE90
classDef minor-edit fill:#87CEEB
classDef context fill:#FFFFFF

Notes

Local Testing Results:

• Unit tests successfully generate junit.xml (75KB file confirmed)
• Playwright configuration now lists tests without script errors
• E2E tests still fail due to authentication setup, but script reference issue is resolved

Potential Risks:

• E2E tests may not generate JUnit XML in CI if authentication issues persist
• CircleCI environment may have different file generation timing than local testing

This PR was created with assistance from Devin AI
Link to Devin run: https://app.devin.ai/sessions/bd2b3c122e124b5c8c33c70100252188
Requested by: @timfee