feat(map): multiple marked stations per grid with pin-to-top

- MarkedStation storage upgraded to an ordered list per grid
  (Map<String, List<MarkedStation>>); JSON array shape with legacy
  v14.1 single-object migration on read
- MapAction: SetMarkedStation appends (duplicate callsign ignored),
  RemoveMarkedStation deletes by callsign, PinMarkedStation moves a
  mark to the top of the list
- MaidenheadGridOverlay: red fill for any marked grid unchanged;
  first-call label mode shows the FIRST (pinned) marked callsign
- MapScreen: one row per mark (pale-yellow callsign), pin icon
  (冖 + stroke ↑, drawn in-app) left of the Marked label — shown only
  when the grid has 2+ marks; pinned row's icon grey, others pale
  yellow; delete icon per row
- New ic_pin.xml vector drawable; strings grid_mark_pin

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/SettingsRepo.kt

@@ -270,22 +270,35 @@ class SettingsRepo(
     }
 
     // Marked stations in unworked gridsquares, persisted as a single JSON
-    // object: {"OL62":{"c":call,"t":epochMs}}. One mark per grid.
+    // object: {"OL62":[{"c":call,"t":epochMs}, ...]}. Each grid holds an
+    // ordered list (first = pinned/top). v14.1 stored a single object per
+    // grid; reads transparently migrate that old shape to a one-element list.
     private val keyMarkedGridStations = "markedGridStations"
 
-    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> {
+    override fun getMarkedGridStations(): Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>> {
         val json = preferences.getString(keyMarkedGridStations, null).orEmpty()
         if (json.isBlank()) return emptyMap()
         return try {
             val root = org.json.JSONObject(json)
-            val result = mutableMapOf<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>()
+            val result = mutableMapOf<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>>()
             for (grid in root.keys()) {
-                val o = root.optJSONObject(grid) ?: continue
-                val call = o.optString("c").ifBlank { continue }
-                result[grid] = com.rtbishop.look4sat.core.domain.model.MarkedStation(
-                    call = call,
-                    epochMs = o.optLong("t")
-                )
+                val value = root.opt(grid)
+                val list = when (value) {
+                    // v14.2+ shape: JSON array of station objects.
+                    is org.json.JSONArray -> (0 until value.length()).mapNotNull { i ->
+                        val o = value.optJSONObject(i) ?: return@mapNotNull null
+                        val call = o.optString("c").ifBlank { return@mapNotNull null }
+                        com.rtbishop.look4sat.core.domain.model.MarkedStation(call = call, epochMs = o.optLong("t"))
+                    }
+                    // v14.1 legacy shape: a single station object per grid.
+                    is org.json.JSONObject -> {
+                        val call = value.optString("c").ifBlank { null }
+                        if (call == null) emptyList()
+                        else listOf(com.rtbishop.look4sat.core.domain.model.MarkedStation(call = call, epochMs = value.optLong("t")))
+                    }
+                    else -> emptyList()
+                }
+                if (list.isNotEmpty()) result[grid] = list
             }
             result
         } catch (_: Exception) {
@@ -293,15 +306,18 @@ class SettingsRepo(
         }
     }
 
-    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) {
+    override fun setMarkedGridStations(stations: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>>) {
         val root = org.json.JSONObject()
-        for ((grid, station) in stations) {
-            root.put(
-                grid,
-                org.json.JSONObject()
-                    .put("c", station.call)
-                    .put("t", station.epochMs)
-            )
+        for ((grid, list) in stations) {
+            val array = org.json.JSONArray()
+            for (station in list) {
+                array.put(
+                    org.json.JSONObject()
+                        .put("c", station.call)
+                        .put("t", station.epochMs)
+                )
+            }
+            root.put(grid, array)
         }
         preferences.edit { putString(keyMarkedGridStations, root.toString()) }
     }

core/data/src/test/java/com/rtbishop/look4sat/core/data/repository/DatabaseRepoTest.kt

@@ -313,9 +313,9 @@ private class FakeSettingsRepo(dataSources: DataSourcesSettings = defaultDataSou
         roamedGrids.value = grids
     }
 
-    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
+    override fun getMarkedGridStations(): Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>> = emptyMap()
 
-    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) = Unit
+    override fun setMarkedGridStations(stations: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>>) = Unit
 }
 
 private fun defaultDataSourcesSettings(): DataSourcesSettings {

core/data/src/test/java/com/rtbishop/look4sat/core/data/repository/SelectionRepoSearchTest.kt

@@ -189,8 +189,8 @@ private class FakeSettingsRepoForSearch : ISettingsRepo {
     override fun setWorkedGridQsos(qsos: Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>>) = Unit
     override fun getRoamedGrids(): Set<String> = emptySet()
     override fun setRoamedGrids(grids: Set<String>) = Unit
-    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
-    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) = Unit
+    override fun getMarkedGridStations(): Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>> = emptyMap()
+    override fun setMarkedGridStations(stations: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>>) = Unit
     override fun updateLoTWSettings(settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings) = Unit
     override fun getLastLotwSyncDate(): String = ""
     override fun setLastLotwSyncDate(date: String) = Unit

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ISettingsRepo.kt

@@ -106,10 +106,10 @@ interface ISettingsRepo {
     fun getRoamedGrids(): Set<String>
     fun setRoamedGrids(grids: Set<String>)
     /** Stations the user marked as "want to contact" in unworked gridsquares
-     *  (grid -> mark). One mark per grid; cleared automatically when the grid
-     *  becomes worked. */
-    fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>
-    fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>)
+     *  (grid -> ordered list of marks; the first is the pinned/top one). The
+     *  whole grid clears automatically once it becomes worked. */
+    fun getMarkedGridStations(): Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>>
+    fun setMarkedGridStations(stations: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>>)
     //endregion
 
     //region # LoTW confirmed-grids settings

core/domain/src/test/java/com/rtbishop/look4sat/core/domain/repository/LoTWGridSyncTest.kt

@@ -262,9 +262,9 @@ class LoTWGridSyncTest {
         override fun setWorkedGridQsos(qsos: Map<String, List<GridQso>>) { workedGridQsos = qsos }
         override fun getRoamedGrids(): Set<String> = roamedGrids
         override fun setRoamedGrids(grids: Set<String>) { roamedGrids = grids }
-        private var markedGridStations: Map<String, MarkedStation> = emptyMap()
-        override fun getMarkedGridStations(): Map<String, MarkedStation> = markedGridStations
-        override fun setMarkedGridStations(stations: Map<String, MarkedStation>) { markedGridStations = stations }
+        private var markedGridStations: Map<String, List<MarkedStation>> = emptyMap()
+        override fun getMarkedGridStations(): Map<String, List<MarkedStation>> = markedGridStations
+        override fun setMarkedGridStations(stations: Map<String, List<MarkedStation>>) { markedGridStations = stations }
         override fun getLastLotwSyncDate(): String = lastSyncDate
         override fun setLastLotwSyncDate(date: String) { lastSyncDate = date }
         override fun getLastLotwSyncCallsign(): String = lastSyncCallsign

core/presentation/src/main/res/drawable/ic_pin.xml

@@ -0,0 +1,20 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <!-- 冖 (秃宝盖): 顶横 + 两侧短竖, 笔画型 -->
+    <path
+        android:pathData="M5,4 L19,4 M5,4 L5,8.5 M19,4 L19,8.5"
+        android:strokeColor="@android:color/white"
+        android:strokeWidth="2"
+        android:strokeLineCap="round"
+        android:fillColor="#00000000" />
+    <!-- 笔画型向上箭头 ↑: 竖杆 + 两斜线箭头头 -->
+    <path
+        android:pathData="M12,9 L12,20 M12,9 L7.5,14 M12,9 L16.5,14"
+        android:strokeColor="@android:color/white"
+        android:strokeWidth="2"
+        android:strokeLineCap="round"
+        android:fillColor="#00000000" />
+</vector>

core/presentation/src/main/res/values-zh/strings.xml

@@ -137,6 +137,7 @@
     <string name="grid_mark_confirm">标记</string>
     <string name="grid_mark_label">标记</string>
     <string name="grid_mark_delete">删除标记</string>
+    <string name="grid_mark_pin">置顶</string>
     <string name="map_visible">日照中</string>
 
     <!-- Settings screen -->

core/presentation/src/main/res/values/strings.xml

@@ -157,6 +157,7 @@
     <string name="grid_mark_confirm">Mark</string>
     <string name="grid_mark_label">Marked</string>
     <string name="grid_mark_delete">Remove mark</string>
+    <string name="grid_mark_pin">Pin to top</string>
     <string name="map_visible">Visible</string>
 
     <!-- Settings screen -->

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MaidenheadGridOverlay.kt

@@ -93,9 +93,10 @@ class MaidenheadGridOverlay : Overlay() {
     var workedGrids: Set<String> = emptySet()
 
     /** Marked gridsquares (4-char, uppercase) — unworked grids the user has
-     *  marked a station they want to contact in; drawn red, same alpha as the
-     *  green worked fill. Value carries the marked callsign for label mode. */
-    var markedGrids: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
+     *  marked stations they want to contact in; drawn red, same alpha as the
+     *  green worked fill. Value is the ordered mark list (first = pinned);
+     *  label mode shows the FIRST marked callsign. */
+    var markedGrids: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>> = emptyMap()
 
     /** Grid-mode first-call labels: label worked (green) cells with the first
      *  callsign worked in that grid instead of the Maidenhead code; non-worked
@@ -449,7 +450,7 @@ class MaidenheadGridOverlay : Overlay() {
                         label in workedGrids -> firstCallsByGrid[label]?.let { call ->
                             canvas.drawText(call, (xLeft + xRight) / 2f, yCenter, firstCallPaint)
                         }
-                        label in markedGrids -> markedGrids[label]?.let { station ->
+                        label in markedGrids -> markedGrids[label]?.firstOrNull()?.let { station ->
                             canvas.drawText(station.call, (xLeft + xRight) / 2f, yCenter, firstCallPaint)
                         }
                     }

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapScreen.kt

@@ -429,13 +429,14 @@ private fun MapScreen(
         WorkedGridQsoDialog(
             grid = grid,
             qsos = uiState.workedGridQsos[grid].orEmpty().sortedBy { it.epochMs },
-            marked = uiState.markedGrids[grid],
+            marked = uiState.markedGrids[grid].orEmpty(),
             isUtc = uiState.isUtc,
             matchCalculating = matchCalculating,
             onDismiss = { selectedGrid = null },
             onMatch = { onMatchGrid(grid) },
             onMark = { call -> onAction(MapAction.SetMarkedStation(grid, call)) },
-            onRemoveMark = { onAction(MapAction.RemoveMarkedStation(grid)) }
+            onRemoveMark = { call -> onAction(MapAction.RemoveMarkedStation(grid, call)) },
+            onPinMark = { call -> onAction(MapAction.PinMarkedStation(grid, call)) }
         )
     }
 }
@@ -446,13 +447,14 @@ private fun MapScreen(
 private fun WorkedGridQsoDialog(
     grid: String,
     qsos: List<com.rtbishop.look4sat.core.domain.model.GridQso>,
-    marked: com.rtbishop.look4sat.core.domain.model.MarkedStation?,
+    marked: List<com.rtbishop.look4sat.core.domain.model.MarkedStation>,
     isUtc: Boolean,
     matchCalculating: Boolean,
     onDismiss: () -> Unit,
     onMatch: () -> Unit,
     onMark: (String) -> Unit,
-    onRemoveMark: () -> Unit
+    onRemoveMark: (String) -> Unit,
+    onPinMark: (String) -> Unit
 ) {
     var showMarkInput by remember { mutableStateOf(false) }
     var callInput by remember { mutableStateOf("") }
@@ -512,11 +514,20 @@ private fun WorkedGridQsoDialog(
                         .heightIn(max = 380.dp)
                         .verticalScroll(rememberScrollState())
                 ) {
-                    // A marked station shows first as a red reminder row: red
-                    // callsign, "标记" in the count column, the marking date in
-                    // the date column, and a small delete icon to remove it.
-                    if (marked != null) {
-                        MarkedStationRow(marked = marked, isUtc = isUtc, onRemoveMark = onRemoveMark)
+                    // Marked stations show first as red reminder rows: pale-yellow
+                    // callsign, "标记" in the count column, the marking date in the
+                    // date column, a small pin icon (first = pinned, grey; others
+                    // pale yellow) and a delete icon to remove the mark.
+                    val showPin = marked.size > 1
+                    marked.forEachIndexed { index, station ->
+                        MarkedStationRow(
+                            marked = station,
+                            isPinned = index == 0,
+                            showPin = showPin,
+                            isUtc = isUtc,
+                            onRemoveMark = { onRemoveMark(station.call) },
+                            onPinMark = { onPinMark(station.call) }
+                        )
                         androidx.compose.material3.HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant.copy(alpha = 0.3f))
                     }
                     if (qsos.isNotEmpty()) {
@@ -535,7 +546,7 @@ private fun WorkedGridQsoDialog(
                     if (qsos.isEmpty()) {
                         TextButton(
                             onClick = {
-                                callInput = marked?.call.orEmpty()
+                                callInput = ""
                                 showMarkInput = true
                             },
                             modifier = Modifier.fillMaxWidth()
@@ -585,8 +596,11 @@ private fun WorkedGridQsoDialog(
 @Composable
 private fun MarkedStationRow(
     marked: com.rtbishop.look4sat.core.domain.model.MarkedStation,
+    isPinned: Boolean,
+    showPin: Boolean,
     isUtc: Boolean,
-    onRemoveMark: () -> Unit
+    onRemoveMark: () -> Unit,
+    onPinMark: () -> Unit
 ) {
     Row(
         verticalAlignment = Alignment.CenterVertically,
@@ -596,18 +610,37 @@ private fun MarkedStationRow(
             text = marked.call,
             style = MaterialTheme.typography.titleMedium,
             fontFamily = androidx.compose.ui.text.font.FontFamily.Monospace,
-            color = ComposeColor(0xFFFF3B30),
+            color = ComposeColor(0xFFFFE082),
             maxLines = 1,
             overflow = androidx.compose.ui.text.style.TextOverflow.Ellipsis,
             modifier = Modifier.weight(1f)
         )
-        Text(
-            text = stringResource(R.string.grid_mark_label),
-            style = MaterialTheme.typography.bodySmall,
-            color = MaterialTheme.colorScheme.onSurfaceVariant,
-            textAlign = androidx.compose.ui.text.style.TextAlign.Center,
+        // "标记" column: pin icon (only when the grid has multiple marks) sits
+        // left of the label; pinned (first) row's icon is grey, others pale
+        // yellow — tapping moves that mark to the top.
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.Center,
             modifier = Modifier.weight(1f)
-        )
+        ) {
+            if (showPin) {
+                Icon(
+                    painter = painterResource(R.drawable.ic_pin),
+                    contentDescription = stringResource(R.string.grid_mark_pin),
+                    tint = if (isPinned) ComposeColor(0xFF9E9E9E) else ComposeColor(0xFFFFE082),
+                    modifier = Modifier
+                        .size(18.dp)
+                        .clickable(onClick = onPinMark)
+                )
+                Spacer(Modifier.width(2.dp))
+            }
+            Text(
+                text = stringResource(R.string.grid_mark_label),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                textAlign = androidx.compose.ui.text.style.TextAlign.Center
+            )
+        }
         Row(
             verticalAlignment = Alignment.CenterVertically,
             horizontalArrangement = Arrangement.End,
@@ -1056,7 +1089,7 @@ private fun setGridMode(
     centerOnStation: Boolean = false,
     showFirstCallLabels: Boolean = false,
     firstCallsByGrid: Map<String, String> = emptyMap(),
-    markedGrids: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
+    markedGrids: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>> = emptyMap()
 ) {
     try {
         val gridOverlay = mapView.overlays[OVERLAY_GRID]

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapState.kt

@@ -34,8 +34,9 @@ data class MapState(
     val workedGridQsos: Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>> = emptyMap(),
     /** 4-char gridsquares the station operated from (LoTW MY_GRIDSQUARE) — blue stripes. */
     val roamedGrids: Set<String> = emptySet(),
-    /** Stations the user marked in unworked gridsquares (grid -> mark) — red fill. */
-    val markedGrids: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap(),
+    /** Stations the user marked in unworked gridsquares (grid -> ordered list;
+     *  first = pinned/top) — red fill. */
+    val markedGrids: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>> = emptyMap(),
     val stationPosition: GeoPos? = null,
     val orbitalPass: OrbitalPass,
     val track: List<List<GeoPos>>? = null,
@@ -55,7 +56,8 @@ sealed interface MapAction {
     data class ToggleGridMode(val value: Boolean) : MapAction
     data class ToggleFirstCallLabels(val value: Boolean) : MapAction
     data class SetMarkedStation(val grid: String, val call: String) : MapAction
-    data class RemoveMarkedStation(val grid: String) : MapAction
+    data class RemoveMarkedStation(val grid: String, val call: String) : MapAction
+    data class PinMarkedStation(val grid: String, val call: String) : MapAction
     data class SetVisible(val isVisible: Boolean) : MapAction
 }
 

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapViewModel.kt

@@ -121,19 +121,37 @@ class MapViewModel(
             is MapAction.ToggleGridMode -> settingsRepo.updateOtherSettings { it.copy(stateOfMapGrid = action.value) }
             is MapAction.ToggleFirstCallLabels -> settingsRepo.updateOtherSettings { it.copy(stateOfMapFirstCall = action.value) }
             is MapAction.SetMarkedStation -> {
-                val updated = settingsRepo.getMarkedGridStations() +
-                    (action.grid to com.rtbishop.look4sat.core.domain.model.MarkedStation(
-                        call = action.call.trim().uppercase(),
-                        epochMs = System.currentTimeMillis()
-                    ))
+                val call = action.call.trim().uppercase()
+                val existing = settingsRepo.getMarkedGridStations()
+                val current = existing[action.grid].orEmpty()
+                // 重复呼号忽略: 同一网格已标记过的呼号不再重复添加.
+                val updated = if (current.any { it.call == call }) existing
+                else existing + (action.grid to current + com.rtbishop.look4sat.core.domain.model.MarkedStation(
+                    call = call,
+                    epochMs = System.currentTimeMillis()
+                ))
                 settingsRepo.setMarkedGridStations(updated)
                 _uiState.update { it.copy(markedGrids = updated) }
             }
             is MapAction.RemoveMarkedStation -> {
-                val updated = settingsRepo.getMarkedGridStations() - action.grid
+                val existing = settingsRepo.getMarkedGridStations()
+                val current = existing[action.grid].orEmpty()
+                val remaining = current.filterNot { it.call == action.call }
+                val updated = if (remaining.isEmpty()) existing - action.grid
+                else existing + (action.grid to remaining)
                 settingsRepo.setMarkedGridStations(updated)
                 _uiState.update { it.copy(markedGrids = updated) }
             }
+            is MapAction.PinMarkedStation -> {
+                val existing = settingsRepo.getMarkedGridStations()
+                val current = existing[action.grid].orEmpty()
+                val target = current.firstOrNull { it.call == action.call }
+                if (target != null) {
+                    val updated = existing + (action.grid to listOf(target) + current.filterNot { it.call == action.call })
+                    settingsRepo.setMarkedGridStations(updated)
+                    _uiState.update { it.copy(markedGrids = updated) }
+                }
+            }
             is MapAction.SetVisible -> isScreenVisible.value = action.isVisible
         }
     }

feature/mutual/src/test/java/com/rtbishop/look4sat/feature/mutual/Fakes.kt

@@ -115,8 +115,8 @@ class FakeSettingsRepo(initialPosition: GeoPos = GeoPos(23.13, 113.26)) : ISetti
     override fun setWorkedGridQsos(qsos: Map<String, List<GridQso>>) = TODO()
     override fun getRoamedGrids(): Set<String> = TODO()
     override fun setRoamedGrids(grids: Set<String>) = TODO()
-    override fun getMarkedGridStations(): Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation> = emptyMap()
-    override fun setMarkedGridStations(stations: Map<String, com.rtbishop.look4sat.core.domain.model.MarkedStation>) = Unit
+    override fun getMarkedGridStations(): Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>> = emptyMap()
+    override fun setMarkedGridStations(stations: Map<String, List<com.rtbishop.look4sat.core.domain.model.MarkedStation>>) = Unit
     override fun updateLoTWSettings(settings: LoTWSettings) = TODO()
     override fun getLastLotwSyncDate(): String = ""
     override fun setLastLotwSyncDate(date: String) = Unit