feat(roaming): faithful QTH定位器 port, live-update toggle, night-mode safe

Rework the Roaming page after user review. It is now a faithful port of the QTH定位器 location panel, not a loose re-skin:

UI (matching the reference layout):
- GPS status dot (real: green when a fresh fix exists, outline when stale/missing) + date + time header
- Lat/Lon rows with DMS and 5-decimal display, big 8-char locator centered below
- 3x3 grid of neighboring 4-char squares with the reference proportions: center column ~2.6x wider (21.4% : 56.2% : 21.4%) and center row the tallest (31.5% : 35.9% : 31.7%); red position marker now placed at the fractional position of the fix inside the center cell (was fixed center)
- No oversized GPS button: live updating is now a Settings toggle '漫游位置实时更新' (stateOfRoamingLive, default on) that drives periodic location refresh

Style & night-mode safety:
- All colors come from MaterialTheme.colorScheme (surfaceVariant/secondaryContainer/error) — no hardcoded cyan/blue from the original app. The red night filter (ColorMatrix keeping only the R channel) blanked the old hardcoded palette; theme colors survive it.
- Chinese nav label '漫游' added to values-zh (was missing, showing English 'Roaming')

Settings:
- OtherSettings.stateOfRoamingLive persisted (default true), toggle row in Other card, height adjusted

Verified: feature:roaming, feature:settings, app compile clean.

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsScreen.kt

@@ -488,7 +488,7 @@ private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Uni
     ElevatedCard(
         modifier = Modifier
             .fillMaxWidth()
-            .height(268.dp)
+            .height(296.dp)
     ) {
         Column(modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)) {
             Text(
@@ -510,6 +510,9 @@ private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Uni
             SwitchRow(R.string.prefs_other_switch_night_mode, settings.stateOfNightMode) {
                 onAction(SettingsAction.ToggleNightMode(it))
             }
+            SwitchRow(R.string.prefs_other_switch_roaming_live, settings.stateOfRoamingLive) {
+                onAction(SettingsAction.ToggleRoamingLive(it))
+            }
         }
     }
 }

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsState.kt

@@ -64,6 +64,7 @@ sealed interface SettingsAction {
     data class ToggleSensor(val value: Boolean) : SettingsAction
     data class ToggleLightTheme(val value: Boolean) : SettingsAction
     data class ToggleNightMode(val value: Boolean) : SettingsAction
+    data class ToggleRoamingLive(val value: Boolean) : SettingsAction
 
     // Remote control
     data class UpdateRC(val settings: RCSettings) : SettingsAction

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsViewModel.kt

@@ -121,6 +121,7 @@ class SettingsViewModel(
             is SettingsAction.ToggleSensor -> settingsRepo.updateOtherSettings { it.copy(stateOfSensors = action.value) }
             is SettingsAction.ToggleLightTheme -> settingsRepo.updateOtherSettings { it.copy(stateOfLightTheme = action.value) }
             is SettingsAction.ToggleNightMode -> settingsRepo.updateOtherSettings { it.copy(stateOfNightMode = action.value) }
+            is SettingsAction.ToggleRoamingLive -> settingsRepo.updateOtherSettings { it.copy(stateOfRoamingLive = action.value) }
             // Remote control & data sources
             is SettingsAction.UpdateRC -> settingsRepo.updateRCSettings(action.settings)
             is SettingsAction.UpdateRadioControl -> settingsRepo.updateRadioControlSettings(action.settings)