v0.12.0: simplify backup page app data section

Replace the complex "Alkalmazás adatok" form (checkboxes, paths, volumes,
save button) with a clean read-only status list. Each app shows its name
(linked to its deploy page) and a simple status: Aktív / Inaktív / N/A.

Also include ALL deployed stacks in the list (not just HDD-capable ones),
so apps without user data appear with N/A status.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

controller/internal/backup/appdata.go

@@ -96,10 +96,7 @@ func DiscoverAppData(provider StackDataProvider, backupPrefs map[string]bool, di
 
 		info.BackupEnabled = backupPrefs[stack.Name]
 
-		// Only include apps that have some data to show
-		if info.HasHDDData || len(info.DockerVolumes) > 0 {
-			result = append(result, info)
-		}
+		result = append(result, info)
 	}
 
 	return result