[Bug]: Onsite class changes grid auto-refresh interval is 5 minutes too slow for live event monitoring #5439

Description

Description

The onsite class changes grid (ajax_status.js) auto-refreshes enrollment counts every 5 minutes (300,000ms):

// esp/public/media/scripts/onsite/ajax_status.js, line 1482
setInterval(refresh_counts, 300000);

During live events like Splash, admins need near-real-time visibility into class enrollment and check-in numbers. A 5-minute delay means admins may be making decisions based on stale data — for example, a class could fill up and remain visually "open" for up to 5 minutes.

The refresh_counts() function only fetches lightweight delta data (enrollment_status, checkin_status, full_status ), not the full catalog, so more frequent polling is feasible without significant server load.

Steps to Reproduce

1. Open the onsite class changes grid (/onsite//classchange_grid)
2. Have another admin enroll a student into a class
3. Wait and observe the enrollment count on the grid does not update for up to 5 minutes

Expected Behavior

Enrollment data should refresh every 30–60 seconds for a usable live monitoring experience. Ideally, the interval should be configurable via a Django Tag (e.g., onsite_refresh_interval_ms) so each chapter can tune it for their server capacity

Actual Behavior

Data refreshes every 5 minutes (300,000ms), which is too slow for real-time onsite decision-making.

Screenshots

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Operating System

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Browser

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Additional Context

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