Add comprehensive sparkline chart support as an alternative to progress bars
for CPU, Memory, and Disk metrics across all tables.
Features:
- Toggle between bars/trends view modes (persisted to localStorage)
- 30-second sampling with 2-hour retention window using ring buffer
- Canvas-based rendering with shared requestAnimationFrame for efficiency
- Hover tooltips showing exact values and timestamps
- Threshold reference lines (warning/critical) for context
- localStorage persistence survives page refreshes (12-hour max age)
- Dynamic width adaptation to column size
- Namespaced resource IDs prevent collisions
- Lifecycle cleanup prevents memory leaks
Performance optimizations:
- Decoupled sampling from WebSocket handler (6x reduction in recording)
- O(1) ring buffer insertions (no array cloning)
- Batched canvas rendering (single rAF for all sparklines)
- Debounced localStorage writes
- Automatic pruning of removed resources
UI improvements:
- Consistent radio toggle styling matching other filters
- Fixed column widths prevent layout shift during toggle
- Fixed row heights prevent vertical size changes
- Sparklines fill available column width proportionally
