- Add 4 separate I/O columns (D Read, D Write, N In, N Out) to guest table
- Tighten column widths: fixed-width I/O columns, flexible progress bar columns
- Remove sticky columns from NodeSummaryTable (not needed)
- Shorten "Containers" to "CTs" in node summary for consistency
- Always show full VM/LXC labels (no mobile abbreviation)
- Increase name column minWidth to 100px for mobile readability
- Add formatSpeed utility function for I/O display
- Add responsive infrastructure: useBreakpoint hook, useGridTemplate hook
