04abdafa9a
The daily aggregation now iterates from the since date through the until date and inserts a zero-valued DailyStats entry for any day not already present in the day map. This ensures sparklines and bar charts render a continuous time axis with explicit zeros for idle days, rather than connecting adjacent data points across gaps. Also switch config file creation to os.OpenFile with explicit 0600 permissions and O_WRONLY|O_CREATE|O_TRUNC flags, matching the intent of the original os.Create call while making the restricted permission bits explicit for security.