chore(constants): refactor loose interval constants into one place DEV-2487

[duvld]

🗒️ Checklist

1. run linter locally
2. update developer docs (API, README, inline, etc.), if any
3. for user-facing doc changes create a Zulip thread at #Support Docs Updates, if any
4. draft PR with a title <type>(<scope>)<!>: <title> DEV-1234
5. assign yourself, tag PR: at least Front end and/or Back end or workflow
6. fill in the template below and delete template comments
7. review thyself: read the diff and repro the preview as written
8. open PR & confirm that CI passes & request reviewers, if needed
9. act on any greptile review below a 5/5 score or leave comment explaining why you won't
10. delete this checklist section from the final squash commit before merging

📣 Summary

Internal refactor

💭 Notes

Primarily done by robot. Verified by my eyes and testing a few places

👀 Preview steps

1. Navigate to places that have polling intervals such as table search, bulk processing, activity monitor and check that there is still polling delays in place
2. Read the code and double check the values changed are correct

[greptile-apps]

Greptile Summary

This PR centralizes frontend polling intervals in jsapp/js/constants.ts while preserving the existing timing behavior.

• Replaces local polling literals and constants across activity, imports, processing, submissions, and help messaging.
• Converts bulk-action polling bounds from seconds to milliseconds without changing the resulting intervals.
• Exposes the new intervals through named exports and the constants default export.

Confidence Score: 5/5

The PR appears safe to merge because the centralized constants preserve the prior polling values, units, and scheduling behavior.

The moved values are equivalent to their prior literals, the bulk-action unit conversion preserves every calculation branch, and the new imports resolve through a runtime-dependency-free constants module.

_{Reviews (1): Last reviewed commit: "Robot refactor" | Re-trigger Greptile}