e4e1d1da49
Two related bugs where the server defaulted naive datetimes to UTC instead of the configured user timezone, causing all-day events to land on the previous day and briefings to "disappear" at UTC midnight. - New services/tz.py helpers: get_user_tz, user_today, user_briefing_date (the briefing day flips at 4am local to align with the compilation slot, so the 00:00-04:00 local window still shows yesterday's briefing until the new one is generated). - calendar create/list/update tools now parse naive datetimes in the user's TZ before converting to UTC for storage, and tool descriptions tell the model to pass plain local dates. - briefing_conversations.get_or_create_today_conversation and the reset-today route use user_briefing_date so the in-progress briefing doesn't get replaced at 19:00 NY / UTC midnight. - _run_profile_closeout targets user-local "yesterday" for consistency. Regression tests added for the TZ helpers and the calendar tool. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>