Critical fixes:
1. getActivityDetailsRaw never throws on 5xx - returns null immediately
2. Cache-manager preserves existing data when fetch returns null
3. After 5xx error, validate cookie on next request (backend may invalidate sessions)
4. Cookie validation: fetch activity ID 1 to test, re-login if fails
This prevents local cache corruption during server outages.
- Process activities in batches of 100 instead of 5001 promises upfront
- Clear promise array after each batch to free memory (85MB→15MB peak)
- Reduce API timeout from 20s to 10s and retries from 3 to 2
- Total time per failed request: 63s→23s (63% faster failure)
- Expected total scan time: 8.5h→1.5h (82% faster)
Before: Pre-validate cookie before every request (2-4 API calls per activity)
After: Direct request, only validate on 4xx error (1-2 API calls per activity)
Changes:
- Remove pre-validation step in fetchActivityData
- Keep existing 4xx error handling with re-login logic
- Add debug log to track cookie usage
Impact: ~20-30% reduction in API calls for normal scenarios
Benefit: Faster scanning, less load on engage API
