Fix cache tier test to match actual configuration

- Update test expectations from 5s to 2s intervals for realtime tier
- Fix comment to reflect actual 2s interval instead of outdated 5s reference
- All tests now pass correctly

CLAUDE.md

@@ -367,6 +367,15 @@ Agent → ["cpu_load_1min", "memory_usage_percent", ...] → Dashboard → Widge
 - [x] Fixed disk metrics permission issues in systemd collector
 - [x] Enhanced error logging for service directory access problems
 - [x] Optimized service collection focusing on status, memory, and disk metrics only
+- [x] **Comprehensive backup monitoring implementation (2025-10-18)**
+- [x] Added BackupCollector for reading TOML status files with disk space metrics
+- [x] Implemented BackupWidget with disk usage display and service status details
+- [x] Fixed backup script disk space parsing by adding missing capture_output=True
+- [x] Updated backup widget to show actual disk usage instead of repository size
+- [x] Fixed timestamp parsing to use backup completion time instead of start time
+- [x] Resolved timezone issues by using UTC timestamps in backup script
+- [x] Added disk identification metrics (product name, serial number) to backup status
+- [x] Enhanced UI layout with proper backup monitoring integration
 
 **Production Configuration:**
 - CPU load thresholds: Warning ≥ 9.0, Critical ≥ 10.0