fix(privacy): stop telemetry on consent revocation

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

app/(tabs)/settings.tsx

@@ -73,14 +73,26 @@ export default function SettingsScreen() {
   const { settings, hasBiometrics, updateSettings, lock } = useAuth()
   const { notifications, setNotification } = useSettings()
   const [osGranted, setOsGranted] = useState<boolean | null>(null)
+  const [telemetryUpdating, setTelemetryUpdating] = useState(false)
 
   // Telemetry consent: hasTelemetryConsent() returns null (unknown), true, or false.
   // We initialise local state from in-memory value; updates call setTelemetryConsent().
   const [crashReporting, setCrashReporting] = useState<boolean>(hasTelemetryConsent() ?? false)
 
   const handleCrashReportingToggle = useCallback(async (value: boolean) => {
-    setCrashReporting(value)
-    await setTelemetryConsent(value)
+    setTelemetryUpdating(true)
+    try {
+      await setTelemetryConsent(value)
+      setCrashReporting(value)
+    } catch {
+      setCrashReporting(hasTelemetryConsent() ?? false)
+      Alert.alert(
+        "Privacy Setting Not Saved",
+        "Crash reporting is off for this session, but your choice could not be saved. Please try again.",
+      )
+    } finally {
+      setTelemetryUpdating(false)
+    }
   }, [])
 
   // Check OS permission state on first toggle attempt
@@ -193,6 +205,7 @@ export default function SettingsScreen() {
             <Switch
               value={crashReporting}
               onValueChange={handleCrashReportingToggle}
+              disabled={telemetryUpdating}
               trackColor={{ false: "#767577", true: "#22c55e" }}
             />
           }