fix(discovery): unregister packet collector on success, use string resources in settings

- Fix resource leak: collectorRegistry.collector was never cleared in
  the successful scan completion path (only in stop/abort paths)
- Replace hardcoded 'Local Mesh Discovery' strings in both Settings
  screens with stringResource(Res.string.discovery_local_mesh)
- Add missing explicit imports for the CMP string accessor
- Remove redundant .gitkeep files from directories with content

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

feature/discovery/src/commonMain/kotlin/org/meshtastic/feature/discovery/DiscoveryScanEngine.kt

@@ -307,7 +307,8 @@ class DiscoveryScanEngine(
             persistCurrentDwellResults()
         }
 
-        // All presets scanned
+        // All presets scanned — unregister packet collector before analysis
+        collectorRegistry.collector = null
         _scanState.value = DiscoveryScanState.Analysis
         restoreHomePreset()
         generateAiSummaries()

feature/settings/src/androidMain/kotlin/org/meshtastic/feature/settings/SettingsScreen.kt

@@ -46,6 +46,7 @@ import org.meshtastic.core.navigation.SettingsRoute
 import org.meshtastic.core.navigation.WifiProvisionRoute
 import org.meshtastic.core.resources.Res
 import org.meshtastic.core.resources.bottom_nav_settings
+import org.meshtastic.core.resources.discovery_local_mesh
 import org.meshtastic.core.resources.export_configuration
 import org.meshtastic.core.resources.filter_settings
 import org.meshtastic.core.resources.help_and_documentation
@@ -242,8 +243,11 @@ fun SettingsScreen(
                     onShowThemePicker = { showThemePickerDialog = true },
                 )
 
-                ExpressiveSection(title = "Local Mesh Discovery") {
-                    ListItem(text = "Local Mesh Discovery", leadingIcon = MeshtasticIcons.PermScanWifi) {
+                ExpressiveSection(title = stringResource(Res.string.discovery_local_mesh)) {
+                    ListItem(
+                        text = stringResource(Res.string.discovery_local_mesh),
+                        leadingIcon = MeshtasticIcons.PermScanWifi,
+                    ) {
                         onNavigate(DiscoveryRoute.DiscoveryGraph)
                     }
                 }

feature/settings/src/jvmMain/kotlin/org/meshtastic/feature/settings/DesktopSettingsScreen.kt

@@ -49,6 +49,7 @@ import org.meshtastic.core.resources.app_version
 import org.meshtastic.core.resources.bottom_nav_settings
 import org.meshtastic.core.resources.device_db_cache_limit
 import org.meshtastic.core.resources.device_db_cache_limit_summary
+import org.meshtastic.core.resources.discovery_local_mesh
 import org.meshtastic.core.resources.help_and_documentation
 import org.meshtastic.core.resources.info
 import org.meshtastic.core.resources.modules_already_unlocked
@@ -204,8 +205,11 @@ fun DesktopSettingsScreen(
                     )
                 }
 
-                ExpressiveSection(title = "Local Mesh Discovery") {
-                    ListItem(text = "Local Mesh Discovery", leadingIcon = MeshtasticIcons.PermScanWifi) {
+                ExpressiveSection(title = stringResource(Res.string.discovery_local_mesh)) {
+                    ListItem(
+                        text = stringResource(Res.string.discovery_local_mesh),
+                        leadingIcon = MeshtasticIcons.PermScanWifi,
+                    ) {
                         onNavigate(DiscoveryRoute.DiscoveryGraph)
                     }
                 }