Optimize nav location tracking: embedded track detail map, tack detection fixes, dim past tracks

* Fix tack detection and convert track detail to embedded-map fragment

TackDetector: revert STABILITY_MAX to 30° (was tightened too far to 20°),
add 120s start-skip to filter GPS cold-start false positives, keep 45s
minimum gap between tacks.

TrackDetailSheet: convert from BottomSheetDialogFragment to a regular
Fragment with an embedded MapLibreMap in the top half. This fixes the
map centering issue (the embedded map is always sized to its own frame),
eliminates accidental dismissal when dragging the map, and makes the
view self-contained — back navigation restores the track list via the
fragment back stack. Tack markers rendered on the embedded map; tapping
a log event pans the embedded map directly.

https://claude.ai/code/session_01YUbuZNDAoLea4cf9UGQ9qn

* Fix XML conflict markers left in layout_track_detail_sheet.xml

https://claude.ai/code/session_01YUbuZNDAoLea4cf9UGQ9qn

* Fix Kotlin conflict markers left in TrackDetailSheet.kt

https://claude.ai/code/session_01YUbuZNDAoLea4cf9UGQ9qn

* Fix compile errors on feature branch

- SavedTracksFragment/VoiceLogFragment: remove references to SafState,
  safState, launchSafPicker, layout_empty, btn_setup_storage, and
  layout_log_entry — none of these exist on this branch
- TrackStorage: add missing onCancellation lambda to cont.resume()
- build.gradle: enable buildConfig generation (fixes unresolved BuildConfig)

https://claude.ai/code/session_01YUbuZNDAoLea4cf9UGQ9qn

* Dim past tracks: dark navy 0.12 opacity, solid lines

https://claude.ai/code/session_01YUbuZNDAoLea4cf9UGQ9qn

---------

Co-authored-by: Claude <noreply@anthropic.com>

5 files changed, 195 insertions, 113 deletions

diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/SavedTracksFragment.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/SavedTracksFragment.kt
index 44055ce..67f32f6 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/SavedTracksFragment.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/SavedTracksFragment.kt
@@ -34,18 +34,20 @@ class SavedTracksFragment : Fragment() {
             (requireActivity() as MainActivity).hideOverlays()
         }
 
-        val rv             = view.findViewById<RecyclerView>(R.id.rv_saved_tracks)
-        val layoutEmpty    = view.findViewById<View>(R.id.layout_empty)
-        val tvEmpty        = view.findViewById<TextView>(R.id.tv_empty)
-        val btnSetup       = view.findViewById<MaterialButton>(R.id.btn_setup_storage)
+        val rv          = view.findViewById<RecyclerView>(R.id.rv_saved_tracks)
+        val layoutEmpty = view.findViewById<View>(R.id.layout_empty)
+        val tvEmpty     = view.findViewById<TextView>(R.id.tv_empty)
+        val btnSetup    = view.findViewById<MaterialButton>(R.id.btn_setup_storage)
 
         rv.layoutManager = LinearLayoutManager(requireContext())
         rv.addItemDecoration(DividerItemDecoration(requireContext(), DividerItemDecoration.VERTICAL))
 
         val adapter = SavedTrackAdapter { track ->
             viewModel.selectTrack(track)
-            (requireActivity() as MainActivity).hideOverlays()
-            TrackDetailSheet.newInstance().show(parentFragmentManager, "track_detail")
+            parentFragmentManager.beginTransaction()
+                .replace(R.id.fragment_container, TrackDetailSheet.newInstance())
+                .addToBackStack("track_detail")
+                .commit()
         }
         rv.adapter = adapter
 
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TackDetector.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TackDetector.kt
index 3c3385c..9668fd1 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/TackDetector.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TackDetector.kt
@@ -3,11 +3,12 @@ package org.terst.nav.track
 import kotlin.math.abs
 
 object TackDetector {
-    private const val HALF_WIN      = 2
-    private const val MIN_DELTA     = 60.0
-    private const val MAX_DELTA     = 140.0
-    private const val STABILITY_MAX = 20.0
-    private const val MIN_GAP_MS    = 45_000L   // 45 s minimum between tacks
+    private const val HALF_WIN       = 2
+    private const val MIN_DELTA      = 60.0
+    private const val MAX_DELTA      = 140.0
+    private const val STABILITY_MAX  = 30.0
+    private const val MIN_GAP_MS     = 45_000L    // 45 s minimum between tacks
+    private const val START_SKIP_MS  = 120_000L   // skip first 2 min (GPS cold-start noise)
 
     fun detectTacks(points: List<TrackPoint>): List<TackEvent> {
         if (points.size < 2 * HALF_WIN + 1) return emptyList()
@@ -16,6 +17,7 @@ object TackDetector {
         var lastTackMs = Long.MIN_VALUE
 
         for (i in HALF_WIN until points.size - HALF_WIN) {
+            if (points[i].timestampMs - points.first().timestampMs < START_SKIP_MS) continue
             if (points[i].timestampMs - lastTackMs < MIN_GAP_MS) continue
 
             val spreadBefore = abs(angleDiff(points[i - 2].cogDeg, points[i - 1].cogDeg))
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackDetailSheet.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackDetailSheet.kt
index 98205fd..cedf4e1 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackDetailSheet.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackDetailSheet.kt
@@ -5,13 +5,25 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.TextView
+import androidx.fragment.app.Fragment
 import androidx.fragment.app.activityViewModels
 import androidx.recyclerview.widget.DividerItemDecoration
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
-import com.google.android.material.bottomsheet.BottomSheetBehavior
-import com.google.android.material.bottomsheet.BottomSheetDialog
-import com.google.android.material.bottomsheet.BottomSheetDialogFragment
+import org.maplibre.android.camera.CameraUpdateFactory
+import org.maplibre.android.geometry.LatLng
+import org.maplibre.android.geometry.LatLngBounds
+import org.maplibre.android.maps.MapLibreMap
+import org.maplibre.android.maps.MapView
+import org.maplibre.android.maps.Style
+import org.maplibre.android.style.layers.CircleLayer
+import org.maplibre.android.style.layers.LineLayer
+import org.maplibre.android.style.layers.PropertyFactory
+import org.maplibre.android.style.sources.GeoJsonSource
+import org.maplibre.geojson.Feature
+import org.maplibre.geojson.FeatureCollection
+import org.maplibre.geojson.LineString
+import org.maplibre.geojson.Point
 import org.terst.nav.R
 import org.terst.nav.ui.MainViewModel
 import java.time.Instant
@@ -30,9 +42,11 @@ data class LogEvent(
     val detail: String
 )
 
-class TrackDetailSheet : BottomSheetDialogFragment() {
+class TrackDetailSheet : Fragment() {
 
     private val viewModel: MainViewModel by activityViewModels()
+    private lateinit var trackMapView: MapView
+    private var trackMap: MapLibreMap? = null
 
     companion object {
         fun newInstance() = TrackDetailSheet()
@@ -43,11 +57,13 @@ class TrackDetailSheet : BottomSheetDialogFragment() {
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         val track = viewModel.selectedTrack.value ?: run {
-            dismiss()
+            parentFragmentManager.popBackStack()
             return
         }
 
-        view.findViewById<View>(R.id.btn_back).setOnClickListener { dismiss() }
+        view.findViewById<View>(R.id.btn_back).setOnClickListener {
+            parentFragmentManager.popBackStack()
+        }
 
         val titleFmt = DateTimeFormatter.ofPattern("dd MMM yyyy · HH:mm", Locale.getDefault())
             .withZone(ZoneId.systemDefault())
@@ -68,20 +84,72 @@ class TrackDetailSheet : BottomSheetDialogFragment() {
         rv.layoutManager = LinearLayoutManager(requireContext())
         rv.addItemDecoration(DividerItemDecoration(requireContext(), DividerItemDecoration.VERTICAL))
         rv.adapter = LogEventAdapter(events) { event ->
-            viewModel.panToTrackPoint(event.lat, event.lon)
+            trackMap?.easeCamera(CameraUpdateFactory.newLatLng(LatLng(event.lat, event.lon)), 300)
         }
 
-        (dialog as? BottomSheetDialog)?.behavior?.apply {
-            isFitToContents = false
-            halfExpandedRatio = 0.5f
-            skipCollapsed = true
-            isDraggable = false
-            state = BottomSheetBehavior.STATE_HALF_EXPANDED
+        trackMapView = view.findViewById(R.id.track_map_view)
+        trackMapView.onCreate(savedInstanceState)
+        trackMapView.getMapAsync { map ->
+            trackMap = map
+            map.setStyle(Style.Builder().fromUri("https://tiles.openfreemap.org/styles/bright")) { style ->
+                drawTrack(style, track.points)
+                drawTacks(style, track.tacks)
+                zoomToTrack(map, track.points)
+            }
         }
-        dialog?.window?.setDimAmount(0.2f)
+    }
+
+    private fun drawTrack(style: Style, points: List<TrackPoint>) {
+        if (points.size < 2) return
+        val source = GeoJsonSource("track-detail-source",
+            Feature.fromGeometry(LineString.fromLngLats(points.map { Point.fromLngLat(it.lon, it.lat) })))
+        style.addSource(source)
+        style.addLayer(LineLayer("track-detail-layer", "track-detail-source").apply {
+            setProperties(
+                PropertyFactory.lineColor("#2B8FC4"),
+                PropertyFactory.lineWidth(4f),
+                PropertyFactory.lineCap("round"),
+                PropertyFactory.lineJoin("round")
+            )
+        })
+    }
+
+    private fun drawTacks(style: Style, tacks: List<TackEvent>) {
+        if (tacks.isEmpty()) return
+        val features = tacks.map { Feature.fromGeometry(Point.fromLngLat(it.lon, it.lat)) }
+        val source = GeoJsonSource("tack-detail-source", FeatureCollection.fromFeatures(features))
+        style.addSource(source)
+        style.addLayer(CircleLayer("tack-detail-layer", "tack-detail-source").apply {
+            setProperties(
+                PropertyFactory.circleColor("#FDD835"),
+                PropertyFactory.circleRadius(7f),
+                PropertyFactory.circleStrokeColor("#F57F17"),
+                PropertyFactory.circleStrokeWidth(2f)
+            )
+        })
+    }
+
+    private fun zoomToTrack(map: MapLibreMap, points: List<TrackPoint>) {
+        if (points.size < 2) return
+        val bounds = LatLngBounds.Builder().apply {
+            points.forEach { include(LatLng(it.lat, it.lon)) }
+        }.build()
+        map.easeCamera(CameraUpdateFactory.newLatLngBounds(bounds, 80), 600)
+    }
+
+    override fun onStart()   { super.onStart();   if (::trackMapView.isInitialized) trackMapView.onStart() }
+    override fun onResume()  { super.onResume();  if (::trackMapView.isInitialized) trackMapView.onResume() }
+    override fun onPause()   { super.onPause();   if (::trackMapView.isInitialized) trackMapView.onPause() }
+    override fun onStop()    { super.onStop();    if (::trackMapView.isInitialized) trackMapView.onStop() }
+    override fun onLowMemory() { super.onLowMemory(); if (::trackMapView.isInitialized) trackMapView.onLowMemory() }
+
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        if (::trackMapView.isInitialized) trackMapView.onSaveInstanceState(outState)
     }
 
     override fun onDestroyView() {
+        if (::trackMapView.isInitialized) trackMapView.onDestroy()
         super.onDestroyView()
         viewModel.clearSelectedTrack()
     }
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/ui/MapHandler.kt b/android-app/app/src/main/kotlin/org/terst/nav/ui/MapHandler.kt
index 0c31024..7614a49 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/ui/MapHandler.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/ui/MapHandler.kt
@@ -315,7 +315,7 @@ class MapHandler(private val maplibreMap: MapLibreMap) {
             style.addLayer(LineLayer(TRACK_PAST_DIM_LAYER_ID, TRACK_PAST_DIM_SOURCE_ID).apply {
                 setProperties(
                     PropertyFactory.lineColor("#0B3050"),
-                    PropertyFactory.lineOpacity(0.22f),
+                    PropertyFactory.lineOpacity(0.12f),
                     PropertyFactory.lineWidth(2.5f),
                     PropertyFactory.lineCap("round"),
                     PropertyFactory.lineJoin("round")
diff --git a/android-app/app/src/main/res/layout/layout_track_detail_sheet.xml b/android-app/app/src/main/res/layout/layout_track_detail_sheet.xml
index 97b1da8..993edf8 100644
--- a/android-app/app/src/main/res/layout/layout_track_detail_sheet.xml
+++ b/android-app/app/src/main/res/layout/layout_track_detail_sheet.xml
@@ -6,107 +6,117 @@
     android:orientation="vertical"
     android:background="?attr/colorSurface">
 
-    <!-- Drag handle -->
-    <View
-        android:layout_width="36dp"
-        android:layout_height="40dp"
-        android:layout_gravity="center_horizontal"
-        android:background="@drawable/drag_handle_bg" />
-
-    <!-- Header -->
+    <!-- Track map — top half -->
+    <org.maplibre.android.maps.MapView
+        android:id="@+id/track_map_view"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1" />
+
+    <!-- Detail panel — bottom half -->
     <LinearLayout
         android:layout_width="match_parent"
-        android:layout_height="56dp"
-        android:orientation="horizontal"
-        android:gravity="center_vertical"
-        android:paddingStart="8dp"
-        android:paddingEnd="16dp"
-        android:elevation="4dp"
+        android:layout_height="0dp"
+        android:layout_weight="1"
+        android:orientation="vertical"
         android:background="?attr/colorSurface">
 
-        <ImageButton
-            android:id="@+id/btn_back"
-            android:layout_width="48dp"
-            android:layout_height="48dp"
-            android:src="@drawable/ic_back"
-            android:background="?attr/selectableItemBackgroundBorderless"
-            android:contentDescription="Back" />
+        <!-- Header -->
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="56dp"
+            android:orientation="horizontal"
+            android:gravity="center_vertical"
+            android:paddingStart="8dp"
+            android:paddingEnd="16dp"
+            android:elevation="4dp"
+            android:background="?attr/colorSurface">
 
-        <TextView
-            android:id="@+id/detail_title"
-            android:layout_width="0dp"
-            android:layout_height="wrap_content"
-            android:layout_weight="1"
-            android:textSize="17sp"
-            android:textStyle="bold"
-            android:layout_marginStart="4dp" />
+            <ImageButton
+                android:id="@+id/btn_back"
+                android:layout_width="48dp"
+                android:layout_height="48dp"
+                android:src="@drawable/ic_back"
+                android:background="?attr/selectableItemBackgroundBorderless"
+                android:contentDescription="Back" />
 
-    </LinearLayout>
+            <TextView
+                android:id="@+id/detail_title"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:textSize="17sp"
+                android:textStyle="bold"
+                android:layout_marginStart="4dp" />
 
-    <!-- Stats row: distance · duration · max · avg -->
-    <LinearLayout
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:orientation="horizontal"
-        android:paddingHorizontal="12dp"
-        android:paddingTop="12dp"
-        android:paddingBottom="12dp">
-
-        <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
-            android:layout_weight="1" android:orientation="vertical" android:gravity="center">
-            <TextView android:id="@+id/detail_distance" android:layout_width="wrap_content"
-                android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
-            <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
-                android:text="nm" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
         </LinearLayout>
 
-        <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
-            android:layout_weight="1" android:orientation="vertical" android:gravity="center">
-            <TextView android:id="@+id/detail_duration" android:layout_width="wrap_content"
-                android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
-            <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
-                android:text="time" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
-        </LinearLayout>
+        <!-- Stats row: distance · duration · max · avg -->
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="horizontal"
+            android:paddingHorizontal="12dp"
+            android:paddingTop="8dp"
+            android:paddingBottom="8dp">
 
-        <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
-            android:layout_weight="1" android:orientation="vertical" android:gravity="center">
-            <TextView android:id="@+id/detail_max_sog" android:layout_width="wrap_content"
-                android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
-            <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
-                android:text="max kt" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
-        </LinearLayout>
+            <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
+                android:layout_weight="1" android:orientation="vertical" android:gravity="center">
+                <TextView android:id="@+id/detail_distance" android:layout_width="wrap_content"
+                    android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
+                <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
+                    android:text="nm" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
+            </LinearLayout>
+
+            <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
+                android:layout_weight="1" android:orientation="vertical" android:gravity="center">
+                <TextView android:id="@+id/detail_duration" android:layout_width="wrap_content"
+                    android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
+                <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
+                    android:text="time" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
+            </LinearLayout>
+
+            <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
+                android:layout_weight="1" android:orientation="vertical" android:gravity="center">
+                <TextView android:id="@+id/detail_max_sog" android:layout_width="wrap_content"
+                    android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
+                <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
+                    android:text="max kt" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
+            </LinearLayout>
+
+            <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
+                android:layout_weight="1" android:orientation="vertical" android:gravity="center">
+                <TextView android:id="@+id/detail_avg_sog" android:layout_width="wrap_content"
+                    android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
+                <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
+                    android:text="avg kt" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
+            </LinearLayout>
 
-        <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content"
-            android:layout_weight="1" android:orientation="vertical" android:gravity="center">
-            <TextView android:id="@+id/detail_avg_sog" android:layout_width="wrap_content"
-                android:layout_height="wrap_content" android:textSize="22sp" android:textStyle="bold" />
-            <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
-                android:text="avg kt" android:textSize="11sp" android:textColor="?attr/colorOnSurfaceVariant" />
         </LinearLayout>
 
-    </LinearLayout>
+        <View android:layout_width="match_parent" android:layout_height="1dp"
+            android:background="?attr/colorOutlineVariant" android:layout_marginHorizontal="16dp" />
 
-    <View android:layout_width="match_parent" android:layout_height="1dp"
-        android:background="?attr/colorOutlineVariant" android:layout_marginHorizontal="16dp" />
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:paddingHorizontal="20dp"
+            android:paddingTop="8dp"
+            android:paddingBottom="4dp"
+            android:text="Event Log"
+            android:textSize="13sp"
+            android:textAllCaps="true"
+            android:letterSpacing="0.08"
+            android:textColor="?attr/colorOnSurfaceVariant" />
 
-    <TextView
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:paddingHorizontal="20dp"
-        android:paddingTop="12dp"
-        android:paddingBottom="4dp"
-        android:text="Event Log"
-        android:textSize="13sp"
-        android:textAllCaps="true"
-        android:letterSpacing="0.08"
-        android:textColor="?attr/colorOnSurfaceVariant" />
-
-    <androidx.recyclerview.widget.RecyclerView
-        android:id="@+id/rv_log_entries"
-        android:layout_width="match_parent"
-        android:layout_height="0dp"
-        android:layout_weight="1"
-        android:clipToPadding="false"
-        android:paddingBottom="24dp" />
+        <androidx.recyclerview.widget.RecyclerView
+            android:id="@+id/rv_log_entries"
+            android:layout_width="match_parent"
+            android:layout_height="0dp"
+            android:layout_weight="1"
+            android:clipToPadding="false"
+            android:paddingBottom="24dp" />
+
+    </LinearLayout>
 
 </LinearLayout>