b14f72a0fb
Fixes launch freeze by running TripPlanningEngine in background task. UI now responsive immediately while trips generate. - Move heavy computation to Task.detached with .userInitiated priority - Change all helper methods to nonisolated static functions - Create local TripPlanningEngine in background task instead of instance property Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>