feat(map): add pulsing online indicator and satellite tile style

- Add animated pulsing ring behind online nodes using Compose
  InfiniteTransition (expanding radius + fading opacity)
- Add Satellite map style using free Esri World Imagery raster tiles
- Use BaseStyle.Json for inline raster style definition
- Derive baseStyle from selectedMapStyle (single source of truth)
- Update MapStyleTest to verify both Uri and Json style variants
- Update MapViewModelTest to use toBaseStyle() assertions

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

Author: jamesarich

.skills/compose-ui/strings-index.txt

@@ -667,6 +667,7 @@
     <string name="map_style_light">Light</string>
     <string name="map_style_osm">OpenStreetMap</string>
     <string name="map_style_road_map">Road Map</string>
+    <string name="map_style_satellite">Satellite</string>
     <string name="map_style_selection">Map style selection</string>
     <string name="map_style_terrain">Terrain</string>
     <string name="map_subDescription">bearing: %1$d° distance: %2$s</string>

core/resources/src/commonMain/composeResources/values/strings.xml

@@ -73,18 +73,16 @@ class MapViewModel(
                 bearing = mapCameraPrefs.cameraBearing.value.toDouble(),
             )
 
-    /** Active map base style. */
-    val baseStyle: StateFlow<BaseStyle> =
-        mapCameraPrefs.selectedStyleUri
-            .map { uri -> if (uri.isBlank()) MapStyle.OpenStreetMap.toBaseStyle() else BaseStyle.Uri(uri) }
-            .stateInWhileSubscribed(MapStyle.OpenStreetMap.toBaseStyle())
-
     /** Currently selected map style enum index. */
     val selectedMapStyle: StateFlow<MapStyle> =
         mapCameraPrefs.selectedStyleUri
             .map { uri -> MapStyle.entries.find { it.styleUri == uri } ?: MapStyle.OpenStreetMap }
             .stateInWhileSubscribed(MapStyle.OpenStreetMap)
 
+    /** Active map base style derived from the selected [MapStyle]. */
+    val baseStyle: StateFlow<BaseStyle> =
+        selectedMapStyle.map { it.toBaseStyle() }.stateInWhileSubscribed(MapStyle.OpenStreetMap.toBaseStyle())
+
     /** Persist camera position to DataStore. */
     fun saveCameraPosition(position: CameraPosition) {
         mapCameraPrefs.setCameraLat(position.target.latitude)

feature/map/src/commonMain/kotlin/org/meshtastic/feature/map/MapViewModel.kt

@@ -16,9 +16,16 @@
  */
 package org.meshtastic.feature.map.component
 
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.RepeatMode
+import androidx.compose.animation.core.animateFloat
+import androidx.compose.animation.core.infiniteRepeatable
+import androidx.compose.animation.core.rememberInfiniteTransition
+import androidx.compose.animation.core.tween
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.rememberUpdatedState
@@ -97,6 +104,9 @@ private const val CLUSTER_OPACITY = 0.85f
 private const val LABEL_OFFSET_EM = 1.5f
 private const val CLUSTER_ZOOM_INCREMENT = 2.0
 private const val HILLSHADE_EXAGGERATION = 0.5f
+private const val PULSE_DURATION_MS = 1500
+private const val PULSE_MAX_RADIUS_DP = 14f
+private const val PULSE_START_OPACITY = 0.5f
 
 /** Free Terrain Tiles (Terrarium encoding) hosted on AWS. No API key required. */
 private val TERRAIN_TILES = listOf("https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png")
@@ -199,6 +209,16 @@ private fun NodeMarkerLayers(
     val labelColor = MaterialTheme.colorScheme.onSurfaceVariant
     val clusterLabelColor = MaterialTheme.colorScheme.onPrimary
 
+    // Pulsing ring animation for online nodes
+    val pulseTransition = rememberInfiniteTransition(label = "node-pulse")
+    val pulseProgress by
+        pulseTransition.animateFloat(
+            initialValue = 0f,
+            targetValue = 1f,
+            animationSpec = infiniteRepeatable(tween(PULSE_DURATION_MS, easing = LinearEasing), RepeatMode.Restart),
+            label = "pulse-progress",
+        )
+
     val nodesSource =
         rememberGeoJsonSource(
             data = GeoJsonData.Features(featureCollection),
@@ -241,6 +261,18 @@ private fun NodeMarkerLayers(
         textSize = const(1.2f.em),
     )
 
+    // Pulsing ring behind online nodes — animated radius expanding outward with fading opacity
+    val pulseRadius = (NODE_MARKER_RADIUS.value + (PULSE_MAX_RADIUS_DP - NODE_MARKER_RADIUS.value) * pulseProgress).dp
+    val pulseOpacity = PULSE_START_OPACITY * (1f - pulseProgress)
+    CircleLayer(
+        id = "node-pulse-ring",
+        source = nodesSource,
+        filter = feature["is_online"].convertToBoolean(),
+        radius = const(pulseRadius),
+        color = const(OnlineStrokeColor),
+        opacity = const(pulseOpacity),
+    )
+
     // Individual node markers with per-node background color and online-status stroke
     CircleLayer(
         id = "node-markers",

feature/map/src/commonMain/kotlin/org/meshtastic/feature/map/component/MaplibreMapContent.kt

@@ -23,12 +23,13 @@ import org.meshtastic.core.resources.map_style_dark
 import org.meshtastic.core.resources.map_style_light
 import org.meshtastic.core.resources.map_style_osm
 import org.meshtastic.core.resources.map_style_road_map
+import org.meshtastic.core.resources.map_style_satellite
 import org.meshtastic.core.resources.map_style_terrain
 
 /**
  * Predefined map tile styles available in the app.
  *
- * Uses free tile sources that do not require API keys. All styles are vector-based and work across platforms.
+ * Uses free tile sources that do not require API keys.
  */
 enum class MapStyle(val label: StringResource, val styleUri: String) {
     /** OpenStreetMap default tiles via OpenFreeMap Liberty style. */
@@ -45,7 +46,25 @@ enum class MapStyle(val label: StringResource, val styleUri: String) {
 
     /** Dark mode style via OpenFreeMap Fiord. */
     Dark(label = Res.string.map_style_dark, styleUri = "https://tiles.openfreemap.org/styles/fiord"),
+
+    /** Satellite imagery via Esri World Imagery (free for non-commercial use). */
+    Satellite(label = Res.string.map_style_satellite, styleUri = SATELLITE_STYLE_URI),
     ;
 
-    fun toBaseStyle(): BaseStyle = BaseStyle.Uri(styleUri)
+    fun toBaseStyle(): BaseStyle = when (this) {
+        Satellite -> BaseStyle.Json(SATELLITE_STYLE_JSON)
+        else -> BaseStyle.Uri(styleUri)
+    }
 }
+
+/** Stable URI used as persistence key for satellite style selection. */
+private const val SATELLITE_STYLE_URI = "satellite://esri-world-imagery"
+
+/**
+ * Inline MapLibre style JSON for raster satellite imagery.
+ *
+ * Uses Esri World Imagery tiles which are free for non-commercial and educational use.
+ */
+@Suppress("MaxLineLength")
+private const val SATELLITE_STYLE_JSON: String =
+    """{"version":8,"name":"Satellite","sources":{"esri-satellite":{"type":"raster","tiles":["https://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/{z}/{y}/{x}"],"tileSize":256,"maxzoom":18,"attribution":"Esri, Maxar, Earthstar Geographics"}},"layers":[{"id":"satellite","type":"raster","source":"esri-satellite"}]}"""

feature/map/src/commonMain/kotlin/org/meshtastic/feature/map/model/MapStyle.kt

@@ -28,7 +28,6 @@ import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.runTest
 import kotlinx.coroutines.test.setMain
-import org.maplibre.compose.style.BaseStyle
 import org.meshtastic.core.repository.PacketRepository
 import org.meshtastic.core.testing.FakeMapCameraPrefs
 import org.meshtastic.core.testing.FakeMapPrefs
@@ -141,7 +140,7 @@ class MapViewModelTest {
     fun baseStyleDefaultsToOpenStreetMap() = runTest(testDispatcher) {
         viewModel.baseStyle.test {
             val style = awaitItem()
-            assertEquals(BaseStyle.Uri(MapStyle.OpenStreetMap.styleUri), style)
+            assertEquals(MapStyle.OpenStreetMap.toBaseStyle(), style)
             cancelAndIgnoreRemainingEvents()
         }
     }
@@ -166,7 +165,7 @@ class MapViewModelTest {
 
             viewModel.selectMapStyle(MapStyle.Dark)
             val darkStyle = awaitItem()
-            assertEquals(BaseStyle.Uri(MapStyle.Dark.styleUri), darkStyle)
+            assertEquals(MapStyle.Dark.toBaseStyle(), darkStyle)
 
             cancelAndIgnoreRemainingEvents()
         }
@@ -177,7 +176,7 @@ class MapViewModelTest {
         // selectedStyleUri defaults to "" in FakeMapCameraPrefs
         viewModel.baseStyle.test {
             val style = awaitItem()
-            assertEquals(BaseStyle.Uri(MapStyle.OpenStreetMap.styleUri), style)
+            assertEquals(MapStyle.OpenStreetMap.toBaseStyle(), style)
             cancelAndIgnoreRemainingEvents()
         }
     }

feature/map/src/commonTest/kotlin/org/meshtastic/feature/map/MapViewModelTest.kt

@@ -25,14 +25,21 @@ import kotlin.test.assertTrue
 class MapStyleTest {
 
     @Test
-    fun toBaseStyle_returnsUriWithCorrectStyleUri() {
-        for (style in MapStyle.entries) {
+    fun toBaseStyle_returnsUriForVectorStyles() {
+        for (style in MapStyle.entries.filter { it != MapStyle.Satellite }) {
             val baseStyle = style.toBaseStyle()
             assertIs<BaseStyle.Uri>(baseStyle)
             assertEquals(style.styleUri, baseStyle.uri)
         }
     }
 
+    @Test
+    fun toBaseStyle_returnsJsonForSatellite() {
+        val baseStyle = MapStyle.Satellite.toBaseStyle()
+        assertIs<BaseStyle.Json>(baseStyle)
+        assertTrue(baseStyle.json.contains("esri-satellite"))
+    }
+
     @Test
     fun allStyles_haveNonBlankUri() {
         for (style in MapStyle.entries) {