Implement multi-disk backup support

- Update BackupData structure to support multiple backup disks
- Scan /var/lib/backup/status/ directory for all status files
- Calculate status icons for backup and disk usage
- Aggregate repository status from all disks
- Update dashboard to display all backup disks with per-disk status
- Display repository list with count and aggregated status

shared/src/agent_data.rs

@@ -176,23 +176,25 @@ pub struct SubServiceMetric {
 /// Backup system data
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct BackupData {
-    pub status: String,
-    pub total_size_gb: Option<f32>,
-    pub repository_health: Option<String>,
-    pub repository_disk: Option<BackupDiskData>,
-    pub last_backup_size_gb: Option<f32>,
-    pub start_time_raw: Option<String>,
+    pub repositories: Vec<String>,
+    pub repository_status: Status,
+    pub disks: Vec<BackupDiskData>,
 }
 
 /// Backup repository disk information
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct BackupDiskData {
     pub serial: String,
-    pub usage_percent: f32,
-    pub used_gb: f32,
-    pub total_gb: f32,
+    pub product_name: Option<String>,
     pub wear_percent: Option<f32>,
     pub temperature_celsius: Option<f32>,
+    pub last_backup_time: Option<String>,
+    pub backup_status: Status,
+    pub disk_usage_percent: f32,
+    pub disk_used_gb: f32,
+    pub disk_total_gb: f32,
+    pub usage_status: Status,
+    pub services: Vec<String>,
 }
 
 impl AgentData {
@@ -233,12 +235,9 @@ impl AgentData {
             },
             services: Vec::new(),
             backup: BackupData {
-                status: "unknown".to_string(),
-                total_size_gb: None,
-                repository_health: None,
-                repository_disk: None,
-                last_backup_size_gb: None,
-                start_time_raw: None,
+                repositories: Vec::new(),
+                repository_status: Status::Unknown,
+                disks: Vec::new(),
             },
         }
     }