Release v2.4.9

• enhancement: mdplot timeseries plots now use simulation time on the bottom x-axis instead of raw timestep index; units are auto-selected by magnitude (ps when total duration < 1000 ps, ns otherwise); the integer timestep index is shown on the top spine via a secondary x-axis; NAMDLogParser.finalize() adds a dt_fs constant column to the energy dataframe so that chained runs with different timestep sizes are handled correctly — simulation time is computed in the plot task as cumsum(dt_fs × ΔTS / 1000) across the concatenated dataframe, which correctly accumulates time across run segments regardless of whether the timestep changes between segments
• enhancement: mdplot timeseries y-axis unit labels now default to the correct physical units for known NAMD output columns (kcal/mol for energy terms, K for temperature, bar for pressure, ų for volume) rather than *; energy quantities whose maximum absolute value exceeds 1000 kcal/mol are automatically scaled by 1/1000 and labeled 1000 kcal/mol to avoid unwieldy tick magnitudes