Add sea foam Kelly app - #1

Summary

Adds the new Datadog App Builder app for Sarah's App Thu, Aug 20, 12:29:57 pm. The app renders a simple centered "kelly" heading in sea foam green and uses the requested App Builder identifier so builds target the correct app.

Changes

• Scaffolded apps/sarah-s-app-thu-aug-20-12-29-57-pm as a Vite React Datadog App workspace.
• Replaced the starter screen with a centered sea foam green "kelly" display.
• Set apps.identifier to 830bc1ff-f937-4ab4-8001-17db0aa5eb7f.
• Regenerated the root package-lock.json and validated the new workspace link entries.
• Normalized missing Datadog site environment values in this app's Vite config so local builds do not fail when DD_SITE is present but empty.

Testing

• git fetch origin master and confirmed origin/master remained 996acaf before and after changes.
• npm install --package-lock-only --ignore-scripts
• npm ci --ignore-scripts
• Confirmed package-lock.json includes apps/sarah-s-app-thu-aug-20-12-29-57-pm and node_modules/sarah-s-app-thu-aug-20-12-29-57-pm.
• npm run typecheck -w apps/sarah-s-app-thu-aug-20-12-29-57-pm
• npm run lint -w apps/sarah-s-app-thu-aug-20-12-29-57-pm
• npm run build -w apps/sarah-s-app-thu-aug-20-12-29-57-pm
• Ran the Vite dev server and verified with Playwright that "kelly" renders with computed color rgb(113, 230, 198).

PR by Bits - View session in Datadog

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