Reset child strikes to 0 when starting a new day session

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/routers/sessions.py

@@ -95,9 +95,15 @@ async def start_session(
     child_result = await db.execute(
         select(Child).where(Child.id == body.child_id, Child.user_id == current_user.id)
     )
-    if not child_result.scalar_one_or_none():
+    child = child_result.scalar_one_or_none()
+    if not child:
         raise HTTPException(status_code=404, detail="Child not found")
 
+    # Reset strikes at the start of each new day
+    if child.strikes != 0:
+        child.strikes = 0
+        await manager.broadcast(body.child_id, {"event": "strikes_update", "strikes": 0})
+
     session_date = body.session_date or date.today()
 
     # Deactivate any existing active session for this child today