Here's a summary of all fixes:

Issue #4 — Skip not clearing med
  File: synculous-client/src/app/dashboard/medications/page.tsx                                           Root cause: Skipped medications were routed to the "Upcoming" section (status === 'skipped' in the
  upcoming condition), so they appeared as if still pending.
  Fix: Removed || status === 'skipped' from the grouping condition. Now skipped meds go to the "Due"
  section where they properly render with the "Skipped" label — same pattern as taken meds showing
  "Taken".

  Issue #5 — "Invested -359m in yourself"

  Files: api/routes/routines.py, synculous-client/src/app/dashboard/page.tsx,
  synculous-client/src/app/dashboard/stats/page.tsx
  Root cause: Session duration was calculated by comparing a naive UTC created_at from PostgreSQL with
  the user's local time (after stripping timezone). For users behind UTC (e.g., CST/UTC-6), this
  produced negative durations (~-359 minutes ≈ -6 hours offset).
  Fix: Added _make_aware_utc() helper that treats naive datetimes as UTC before comparison. Also clamped
   durations to max(0, ...) on both backend and frontend formatTime as a safety net.

  Issue #6 — Push notifications not working

  File: api/routes/notifications.py
  Root cause: Subscribing to push notifications created a push_subscriptions row but never set
  web_push_enabled: true in the notifications table. The scheduler daemon checks web_push_enabled before
   sending, so push notifications were always skipped.
  Fix: When subscribing, also call notifications.setNotificationSettings() to enable web_push_enabled.
  When unsubscribing (and no subscriptions remain), disable it.

api/routes/routines.py

@@ -35,6 +35,14 @@ def _auth(request):
     return user_uuid
 
 
+def _make_aware_utc(dt):
+    """Ensure a datetime is timezone-aware; assume naive datetimes are UTC."""
+    if dt.tzinfo is None:
+        from datetime import timezone as _tz
+        return dt.replace(tzinfo=_tz.utc)
+    return dt
+
+
 def _record_step_result(session_id, step_id, step_index, result, session):
     """Record a per-step result (completed or skipped)."""
     try:
@@ -51,11 +59,8 @@ def _record_step_result(session_id, step_id, step_index, result, session):
             if last_completed:
                 if isinstance(last_completed, str):
                     last_completed = datetime.fromisoformat(last_completed)
-                # Make naive datetimes comparable with aware ones
-                if last_completed.tzinfo is None:
-                    duration_seconds = int((now.replace(tzinfo=None) - last_completed).total_seconds())
-                else:
-                    duration_seconds = int((now - last_completed).total_seconds())
+                last_completed = _make_aware_utc(last_completed)
+                duration_seconds = max(0, int((now - last_completed).total_seconds()))
             else:
                 duration_seconds = None
         else:
@@ -63,10 +68,8 @@ def _record_step_result(session_id, step_id, step_index, result, session):
             if created_at:
                 if isinstance(created_at, str):
                     created_at = datetime.fromisoformat(created_at)
-                if created_at.tzinfo is None:
-                    duration_seconds = int((now.replace(tzinfo=None) - created_at).total_seconds())
-                else:
-                    duration_seconds = int((now - created_at).total_seconds())
+                created_at = _make_aware_utc(created_at)
+                duration_seconds = max(0, int((now - created_at).total_seconds()))
             else:
                 duration_seconds = None
 
@@ -90,11 +93,8 @@ def _complete_session_with_celebration(session_id, user_uuid, session):
     if created_at:
         if isinstance(created_at, str):
             created_at = datetime.fromisoformat(created_at)
-        # Handle naive vs aware datetime comparison
-        if created_at.tzinfo is None:
-            duration_minutes = round((now.replace(tzinfo=None) - created_at).total_seconds() / 60, 1)
-        else:
-            duration_minutes = round((now - created_at).total_seconds() / 60, 1)
+        created_at = _make_aware_utc(created_at)
+        duration_minutes = max(0, round((now - created_at).total_seconds() / 60, 1))
     else:
         duration_minutes = 0