Description
netwatch/diskwatch-inspired: add read/write IOPS + avg per-op latency to the Disk I/O panel, and a gateway + internet (1.1.1.1) latency ping line to the Network panel. psutil + macOS route/ping, no new deps or sudo. Skipped: SMART/temp, per-process net, connection states (need root/tools).
Acceptance Criteria
- #1 Disk R/W IOPS + avg latency shown
- #2 Gateway + net latency ping shown, colored by latency