fix: clarify evaluate_script selector guidance

[luohui1]

Summary

• clarify that evaluate_script runs with standard browser DOM APIs and CSS selectors
• explain that snapshot uids should be passed through args rather than queried as DOM attributes
• add an eval scenario covering UPC table lookup without :contains or uid/ref attribute selectors

Fixes #1892
Fixes #1895

Tests

• npm run build
• npm run docs:generate
• npm run cli:generate
• npm run format
• npm exec eslint -- --cache .
• npm exec prettier -- --check --cache .
• $env:PUPPETEER_EXECUTABLE_PATH='C:\Program Files\Google\Chrome\Application\chrome.exe'; npm run test tests\tools\script.test.ts

Note: npm run check-format passes ESLint and Prettier on this Windows checkout, then exits non-zero because the script's trailing .; is parsed as an extra Prettier path.

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