Monitor tab:
- CPU card: per-core bars (freq-colored), overall usage bar, rolling history chart
- Memory card: breakdown by system/VM/ZFS/Docker/free with progress bars
- Network card: LAN + ext + Tailscale IP display, live RX/TX chart with auto-scale
- Streams card: Emby/Jellyfin/Plex sessions with playback bar and server badges
- GPU card: adds power draw, encode%, decode% meters
- Transcode card: ramdisk vs SSD location pill, session count, flip history
- Canvas chart helpers: vvDrawChart, vvDrawNetChart, vvMeter, vvFmtBps, vvFmtGib
api/monitor.php: adds cpu, mem, net to response payload