Fixes an issue where dates were incorrectly shifted due to timezone handling and ensures the guard assignment dialog updates in real-time after modifications. Additionally, refactors the calculation of needed guards to accurately reflect site service hours and minimum guard requirements.
Replit-Commit-Author: Agent
Replit-Commit-Session-Id: e5565357-90e1-419f-b9a8-6ee8394636df
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/6d543d2c-20b9-4ea6-93fe-70fe9b1d9f80/e5565357-90e1-419f-b9a8-6ee8394636df/TWQ52cO
