Robot Framework Selenium vs Playwright PoC

[jstvz]

Summary

• Add locators_66.py and focused test updates for the API v66 Selenium locator refresh PoC.
• Expand SalesforcePlaywright.py with 10 Playwright keywords plus an E2E comparison suite.
• Add ADR 0004 and reproducible Selenium 4 shadow-DOM evidence recommending a time-bounded Playwright migration path.

Test plan

• uv run pytest cumulusci/robotframework/tests/test_salesforce_locators.py -v
• uv run cci task run robot --org robot-poc -o suites cumulusci/robotframework/tests/salesforce/locators.robot -o vars BROWSER:headlesschrome
• uv run cci task run robot --org robot-poc -o suites cumulusci/robotframework/tests/salesforce/ui.robot -o test "Get Related List Count" -o vars BROWSER:headlesschrome
• Selenium 11-suite battery: 101/102 passed; known remaining failure is Selenium 3 shadow-DOM access to List View Controls.
• Page object suites: 29/34 passed; known failures are inline Setup/Object Manager locators outside the versioned locator system.
• Playwright E2E execution is blocked by a pre-existing wait_until_salesforce_is_ready URL regex bug; ADR 0004 calls this out as Phase M1.

Notes

This branch was rewritten from dev after PR #3974 was closed. It contains only the public PoC/ADR artifacts; no docs/superpowers files are present in the diff or branch history.