Integrate backup metrics into system widget with enhanced disk monitoring

Replace standalone backup widget with compact backup section in system widget displaying disk serial, temperature, wear level, timing, and usage information.

Changes:
- Remove standalone backup widget and integrate into system widget
- Update backup collector to read TOML format from backup script
- Add BackupDiskData structure with serial, usage, temperature, wear fields
- Implement compact backup display matching specification format
- Add time formatting utilities for backup timing display
- Update backup data extraction from TOML with disk space parsing

Version bump to v0.1.149

dashboard/src/ui/widgets/system.rs

@@ -37,6 +37,18 @@ pub struct SystemWidget {
     // Storage metrics (collected from disk metrics)
     storage_pools: Vec<StoragePool>,
     
+    // Backup metrics
+    backup_status: String,
+    backup_last_run: Option<u64>,
+    backup_next_scheduled: Option<u64>,
+    backup_disk_serial: Option<String>,
+    backup_disk_usage_percent: Option<f32>,
+    backup_disk_used_gb: Option<f32>,
+    backup_disk_total_gb: Option<f32>,
+    backup_disk_wear_percent: Option<f32>,
+    backup_disk_temperature: Option<f32>,
+    backup_last_size_gb: Option<f32>,
+    
     // Overall status
     has_data: bool,
 }
@@ -91,6 +103,16 @@ impl SystemWidget {
             tmp_status: Status::Unknown,
             tmpfs_mounts: Vec::new(),
             storage_pools: Vec::new(),
+            backup_status: "unknown".to_string(),
+            backup_last_run: None,
+            backup_next_scheduled: None,
+            backup_disk_serial: None,
+            backup_disk_usage_percent: None,
+            backup_disk_used_gb: None,
+            backup_disk_total_gb: None,
+            backup_disk_wear_percent: None,
+            backup_disk_temperature: None,
+            backup_last_size_gb: None,
             has_data: false,
         }
     }
@@ -170,6 +192,29 @@ impl Widget for SystemWidget {
 
         // Convert storage data to internal format
         self.update_storage_from_agent_data(agent_data);
+
+        // Extract backup data
+        let backup = &agent_data.backup;
+        self.backup_status = backup.status.clone();
+        self.backup_last_run = backup.last_run;
+        self.backup_next_scheduled = backup.next_scheduled;
+        self.backup_last_size_gb = backup.last_backup_size_gb;
+
+        if let Some(disk) = &backup.repository_disk {
+            self.backup_disk_serial = Some(disk.serial.clone());
+            self.backup_disk_usage_percent = Some(disk.usage_percent);
+            self.backup_disk_used_gb = Some(disk.used_gb);
+            self.backup_disk_total_gb = Some(disk.total_gb);
+            self.backup_disk_wear_percent = disk.wear_percent;
+            self.backup_disk_temperature = disk.temperature_celsius;
+        } else {
+            self.backup_disk_serial = None;
+            self.backup_disk_usage_percent = None;
+            self.backup_disk_used_gb = None;
+            self.backup_disk_total_gb = None;
+            self.backup_disk_wear_percent = None;
+            self.backup_disk_temperature = None;
+        }
     }
 }
 
@@ -352,6 +397,116 @@ fn render_pool_drive(drive: &StorageDrive, is_last: bool, lines: &mut Vec<Line<'
 }
 
 impl SystemWidget {
+    /// Render backup section for display
+    fn render_backup(&self) -> Vec<Line<'_>> {
+        let mut lines = Vec::new();
+
+        // First line: serial number with temperature and wear
+        if let Some(serial) = &self.backup_disk_serial {
+            let mut details = Vec::new();
+            if let Some(temp) = self.backup_disk_temperature {
+                details.push(format!("T: {}°C", temp as i32));
+            }
+            if let Some(wear) = self.backup_disk_wear_percent {
+                details.push(format!("W: {}%", wear as i32));
+            }
+
+            let disk_text = if !details.is_empty() {
+                format!("{} {}", serial, details.join(" "))
+            } else {
+                serial.clone()
+            };
+
+            let backup_status = match self.backup_status.as_str() {
+                "completed" | "success" => Status::Ok,
+                "running" => Status::Pending,
+                "failed" => Status::Critical,
+                _ => Status::Unknown,
+            };
+
+            let disk_spans = StatusIcons::create_status_spans(backup_status, &disk_text);
+            lines.push(Line::from(disk_spans));
+
+            // Last backup time
+            if let Some(last_run) = self.backup_last_run {
+                let time_ago = self.format_time_ago(last_run);
+                let last_text = if let Some(size) = self.backup_last_size_gb {
+                    format!("Last: {} ({:.1}GB)", time_ago, size)
+                } else {
+                    format!("Last: {}", time_ago)
+                };
+                
+                lines.push(Line::from(vec![
+                    Span::styled("  ├─ ", Typography::tree()),
+                    Span::styled(last_text, Typography::secondary())
+                ]));
+            }
+
+            // Next backup time
+            if let Some(next_scheduled) = self.backup_next_scheduled {
+                let next_text = format!("Next: {}", self.format_time_until(next_scheduled));
+                lines.push(Line::from(vec![
+                    Span::styled("  ├─ ", Typography::tree()),
+                    Span::styled(next_text, Typography::secondary())
+                ]));
+            }
+
+            // Usage information
+            if let (Some(used), Some(total), Some(usage_percent)) = (
+                self.backup_disk_used_gb, 
+                self.backup_disk_total_gb,
+                self.backup_disk_usage_percent
+            ) {
+                let usage_text = format!("Usage: {:.0}% {:.0}GB/{:.0}GB", usage_percent, used, total);
+                let usage_spans = StatusIcons::create_status_spans(Status::Ok, &usage_text);
+                let mut full_spans = vec![
+                    Span::styled("  └─ ", Typography::tree()),
+                ];
+                full_spans.extend(usage_spans);
+                lines.push(Line::from(full_spans));
+            }
+        }
+
+        lines
+    }
+
+    /// Format time ago from timestamp
+    fn format_time_ago(&self, timestamp: u64) -> String {
+        let now = chrono::Utc::now().timestamp() as u64;
+        let seconds_ago = now.saturating_sub(timestamp);
+        
+        let hours = seconds_ago / 3600;
+        let minutes = (seconds_ago % 3600) / 60;
+        
+        if hours > 0 {
+            format!("{}h ago", hours)
+        } else if minutes > 0 {
+            format!("{}m ago", minutes)
+        } else {
+            "now".to_string()
+        }
+    }
+
+    /// Format time until from future timestamp  
+    fn format_time_until(&self, timestamp: u64) -> String {
+        let now = chrono::Utc::now().timestamp() as u64;
+        if timestamp <= now {
+            return "overdue".to_string();
+        }
+        
+        let seconds_until = timestamp - now;
+        let hours = seconds_until / 3600;
+        let minutes = (seconds_until % 3600) / 60;
+        
+        if hours > 0 {
+            format!("in {}h", hours)
+        } else if minutes > 0 {
+            format!("in {}m", minutes)
+        } else {
+            "soon".to_string()
+        }
+    }
+
     /// Render system widget  
     pub fn render(&mut self, frame: &mut Frame, area: Rect, hostname: &str, config: Option<&crate::config::DashboardConfig>) {
         let mut lines = Vec::new();
@@ -445,6 +600,19 @@ impl SystemWidget {
         let storage_lines = self.render_storage();
         lines.extend(storage_lines);
 
+        // Backup section (if available)
+        if self.backup_status != "unavailable" && self.backup_status != "unknown" {
+            lines.push(Line::from(vec![
+                Span::styled("", Typography::secondary()) // Empty line for spacing
+            ]));
+            lines.push(Line::from(vec![
+                Span::styled("Backup:", Typography::widget_title())
+            ]));
+
+            let backup_lines = self.render_backup();
+            lines.extend(backup_lines);
+        }
+
         // Apply scroll offset
         let total_lines = lines.len();
         let available_height = area.height as usize;