Remove hardcoded pool mount point mappings for true auto-discovery

- Eliminate hardcoded mappings like 'root' -> '/' and 'steampool' -> '/mnt/steampool'
- Use device names directly for physical drives
- Rely on mount_point metrics from agent for actual mount paths
- Implement zero-configuration architecture as specified in CLAUDE.md

dashboard/src/ui/widgets/system.rs

@@ -146,16 +146,14 @@ impl SystemWidget {
         self.agent_hash.as_ref()
     }
 
-    /// Get mount point for a pool name
+    /// Get default mount point for a pool name (fallback only - should use actual mount_point metrics)
     fn get_mount_point_for_pool(&self, pool_name: &str) -> String {
-        match pool_name {
-            "root" => "/".to_string(),
-            "steampool" => "/mnt/steampool".to_string(),
-            "steampool_1" => "/steampool_1".to_string(),
-            "steampool_2" => "/steampool_2".to_string(),
-            // For device names (nvme0n1, sda, etc.), use the device name directly
-            name if name.starts_with("nvme") || name.starts_with("sd") || name.starts_with("hd") => name.to_string(),
-            _ => format!("/{}", pool_name), // Default fallback for mount-based pools
+        // For device names, use the device name directly as display name
+        if pool_name.starts_with("nvme") || pool_name.starts_with("sd") || pool_name.starts_with("hd") {
+            pool_name.to_string()
+        } else {
+            // For other pools, use the pool name as-is (will be overridden by mount_point metric)
+            pool_name.to_string()
         }
     }