fix(stats): make API endpoints timezone-aware to fix sleep session attribution

backend/app/routers/stats.py

@@ -19,6 +19,9 @@ async def get_daily_summary(
     timezone_offset: int = Query(0),
     session: AsyncSession = Depends(get_session),
 ):
+    if to_date.hour == 0 and to_date.minute == 0:
+        to_date = to_date.replace(hour=23, minute=59, second=59, microsecond=999999)
+
     try:
         day_start_time = time.fromisoformat(day_start)
         day_end_time = time.fromisoformat(day_end)
@@ -74,6 +77,9 @@ async def get_timetable(
     timezone_offset: int = Query(0),
     session: AsyncSession = Depends(get_session),
 ):
+    if to_date.hour == 0 and to_date.minute == 0:
+        to_date = to_date.replace(hour=23, minute=59, second=59, microsecond=999999)
+
     utc_from_date = from_date + timedelta(minutes=timezone_offset)
     utc_to_date = to_date + timedelta(minutes=timezone_offset)
     adj_utc_from_date = utc_from_date - timedelta(days=1)
@@ -156,12 +162,15 @@ async def get_wake_sleep_times(
     timezone_offset: int = Query(0),
     session: AsyncSession = Depends(get_session),
 ):
+    if to_date.hour == 0 and to_date.minute == 0:
+        to_date = to_date.replace(hour=23, minute=59, second=59, microsecond=999999)
+
     try:
         w_ref_time = time.fromisoformat(wakeup_ref)
         b_ref_time = time.fromisoformat(bedtime_ref)
     except ValueError:
         return {"days": []}
- 
+
     utc_from_date = from_date + timedelta(minutes=timezone_offset)
     utc_to_date = to_date + timedelta(minutes=timezone_offset)
     adj_utc_from_date = utc_from_date - timedelta(days=1)