- Add PSUReading struct and PSUs []PSUReading to LiveMetricSample - Sample per-PSU input watts from IPMI SDR entity 10.x (Power Supply) - Render stacked filled-area SVG chart (one layer per PSU, cumulative total) - Fall back to single-line chart on systems with ≤1 PSU in SDR Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>