Fix filesystem metric parsing for correct mount point names

- Fix extract_filesystem_metric() to handle multi-underscore metric names correctly
- Parse known metric suffixes (usage_percent, mount_point, available_gb, etc.)
- Prevent incorrect parsing like boot_mount_point -> fs_name='boot_mount', metric_type='point'
- Should now correctly show /boot and / instead of /boot/mount and /root/mount

dashboard/src/ui/widgets/system.rs

@@ -384,11 +384,14 @@ impl SystemWidget {
             if let Some(fs_start) = metric_name.find("_fs_") {
                 let after_fs = &metric_name[fs_start + 4..]; // Skip "_fs_"
                 
-                // Find the last underscore to separate filesystem name from metric type
-                if let Some(last_underscore) = after_fs.rfind('_') {
-                    let fs_name = after_fs[..last_underscore].to_string();
-                    let metric_type = after_fs[last_underscore + 1..].to_string();
-                    return (Some(fs_name), Some(metric_type));
+                // Look for known metric suffixes (these can contain underscores)
+                let known_suffixes = ["usage_percent", "used_gb", "total_gb", "available_gb", "mount_point"];
+                
+                for suffix in known_suffixes {
+                    if after_fs.ends_with(suffix) {
+                        let fs_name = after_fs[..after_fs.len() - suffix.len() - 1].to_string(); // Remove suffix + underscore
+                        return (Some(fs_name), Some(suffix.to_string()));
+                    }
                 }
             }
         }