Add auto-refresh and manual sync for KoboToolbox changes

[langbart]

Problem

When validation status is updated directly in KoboToolbox (outside the portal), the changes are not immediately reflected in the validation portal table. MongoDB is only updated when the R pipeline runs.

Current Behavior

• Portal → MongoDB: ✅ Immediate update
• Portal → KoboToolbox: ✅ Immediate update
• KoboToolbox → MongoDB: ❌ Only updates when R pipeline runs (not real-time)
• Table display: Shows MongoDB data only

Proposed Solution

Phase 1: Auto-refresh (Priority: High)

Add automatic table refresh every 60 seconds to catch:

• Updates from other portal users
• Changes made directly in KoboToolbox
• Background R pipeline syncs

Implementation:

• Add useEffect with interval timer in ValidationTable.tsx
• Call refetch() every 60 seconds
• Clean up interval on component unmount
• Show subtle indicator when refreshing

Benefits:

• Simple implementation
• Covers 99% of use cases
• No infrastructure changes needed
• Handles concurrent users

Phase 2: Manual sync button (Priority: Medium)

Add "Sync from KoboToolbox" button for admin users to trigger on-demand sync.

Implementation:

• Add admin-only button in ValidationTable
• Create API endpoint: POST /api/admin/sync-from-kobo
• Trigger existing R pipeline script
• Show sync progress/status

Benefits:

• Handles rare exceptional cases
• Gives admins control
• Reuses existing R pipeline logic

Phase 3 (Optional): WebSocket real-time updates

For future consideration if real-time updates become critical.

Acceptance Criteria

• ValidationTable auto-refreshes every 60 seconds
• Auto-refresh doesn't disrupt user's current selection/filters
• Visual indicator shows when refresh is in progress
• Manual sync button available for admin users
• Manual sync triggers R pipeline and updates MongoDB
• Sync status/progress is visible to user

Technical Notes

• Auto-refresh interval should be configurable (env var or constant)
• Consider pausing auto-refresh when user is actively editing
• Ensure refresh doesn't reset table state (pagination, filters, sorting)

Related Files

• src/components/ValidationTable/ValidationTable.tsx
• src/api/api.ts (useFetchSubmissions hook)
• api/admin/sync-from-kobo.js (new endpoint needed)

Implementation Estimate

• Phase 1 (Auto-refresh): ~2-3 hours
• Phase 2 (Manual sync): ~4-6 hours
• Testing: ~2 hours

Alternative Considered

Webhooks from KoboToolbox: Rejected due to complexity and infrastructure requirements. The hybrid auto-refresh + manual sync approach is more practical for this use case.