Fix AI timeline generation and evidence loading errors Critical Fixes: - Changed gpt-5-mini to gpt-4o-mini in generate-timeline API - Added temperature parameter (0.7) to all AI API calls - Fixed undefined evidence.forEach crash with null safety - Added DEFAULT_AI_MODEL environment variable support Resolves: - 500 error: 'No content returned from AI' - TypeError: undefined is not an object (evaluating 'evidence.forEach') Deployment: https://1d11f22a.researchtoolspy.pages.dev