fix: explain why native discovery cannot scan stopped containers

AppImage/components/lxc-app-panel.tsx

@@ -125,6 +125,7 @@ interface PortDetail {
 interface NativeDiscovery {
   vmid: number
   status: "not_scanned" | "complete" | "partial" | "error" | "busy"
+  issues?: string[]
   stale: boolean
   candidates: DetectedApp[]
 }
@@ -804,7 +805,10 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData, oci }:
       if (!isCurrent()) return
       setNativeDiscovery(native)
       if (native.status === "error" || native.status === "busy") {
-        setDetectionNotice({ found: false, text: t("vmLxc.appEditor.nativeScanFailed") })
+        const stopped = native.status === "error" && Array.isArray(native.issues)
+          && native.issues.includes("guest_stopped")
+        setDetectionNotice({ found: false, text: t(stopped
+          ? "vmLxc.appEditor.nativeScanStopped" : "vmLxc.appEditor.nativeScanFailed") })
         return
       }
       const result: Suggestions = await fetchApi(`/api/vms/${vmid}/apps/suggestions`, {

AppImage/messages/en/common.json

@@ -1746,6 +1746,7 @@
       "nativeEvidenceDirectory": "Working directory",
       "nativeEvidenceService": "Service definition",
       "nativeScanFailed": "Application search could not finish. Previous evidence may be outdated; try again.",
+      "nativeScanStopped": "This container is stopped. Application search is only available while the container is running.",
       "nativeScanPartial": "Application search is incomplete. Review the available evidence and try again.",
       "nativeVersionUnknown": "Installed version unknown",
       "nativeEvidenceStale": "Evidence may be outdated or incomplete.",

AppImage/messages/sk/common.json

@@ -1690,6 +1690,7 @@
       "nativeEvidenceDirectory": "Pracovný priečinok",
       "nativeEvidenceService": "Definícia služby",
       "nativeScanFailed": "Vyhľadávanie aplikácií sa nepodarilo dokončiť. Predchádzajúce dôkazy môžu byť zastarané; skús to znova.",
+      "nativeScanStopped": "Kontajner je vypnutý. Vyhľadávanie aplikácií je dostupné iba v spustenom kontajneri.",
       "nativeScanPartial": "Vyhľadávanie aplikácií je neúplné. Skontroluj dostupné dôkazy a skús to znova.",
       "nativeVersionUnknown": "Nainštalovaná verzia nie je známa",
       "nativeEvidenceStale": "Dôkazy môžu byť zastarané alebo neúplné.",

AppImage/scripts/tests/test_native_app_discovery.py

@@ -746,6 +746,27 @@ class Routes(unittest.TestCase):
             scan.assert_not_called()
             read.assert_not_called()
 
+    def test_stopped_scan_route_exposes_reason_and_keeps_cached_evidence(self):
+        item = {'discovery_id': 'native-retained', 'name': 'Retained app',
+                'installation_path': '/opt/retained/server'}
+        previous = {'vmid': 101, 'status': 'complete', 'stale': False,
+                    'scanned_at': time.time(), 'candidates': [item]}
+        native._cache[101] = copy.deepcopy(previous)
+        with patch.object(native, 'scan', side_effect=native.ProbeError('guest_stopped')), \
+             patch.object(lxc_apps, 'load_sidecar', return_value={'apps': []}), \
+             patch.object(lxc_apps, 'get_suggestions') as suggestions, \
+             patch.object(lxc_apps, '_write_sidecar') as write:
+            response = self.client.post('/api/vms/101/apps/native-discovery')
+            self.assertEqual(response.status_code, 200)
+            result = response.get_json()
+            self.assertEqual(result['status'], 'error')
+            self.assertEqual(result['issues'], ['guest_stopped'])
+            self.assertTrue(result['stale'])
+            self.assertEqual(result['candidates'], [item])
+            self.assertEqual(result['scanned_at'], previous['scanned_at'])
+            suggestions.assert_not_called()
+            write.assert_not_called()
+
     def test_actual_lifecycle_marks_last_known_stale_without_scanning(self):
         native._cache[101] = {'vmid': 101, 'status': 'complete', 'stale': False,
                               'candidates': [], 'scanned_at': time.time()}