feat: Implement MOB (Man Overboard) alarm functionality

This commit introduces the core functionality for the Man Overboard (MOB) alarm.

Key changes include:
- Added a persistent, high-contrast red MOB Floating Action Button to the UI.
- Implemented dynamic location permission requests and initialization of LocationService.
- Created a MobWaypoint data class to store MOB location and timestamp.
- Developed the activateMob() function to:
  - Capture current GPS coordinates.
  - Set the active MOB waypoint and mark MOB as activated.
  - Switch to a dedicated MOB navigation view, hiding other UI elements.
  - Start a continuous, looping audible alarm (assumes R.raw.mob_alarm exists).
  - Log the MOB event to the console (placeholder for future logbook integration).
- Implemented a MOB navigation view (ConstraintLayout) with real-time distance to MOB and elapsed time display.
- Added a recoverMob() function, triggered by a 'Recovered' button, to:
  - Deactivate MOB mode.
  - Stop and release the audible alarm.
  - Restore the main UI visibility.
- Location updates are observed to continuously update the MOB navigation display.
- Ensured MediaPlayer resources are properly released on activity destruction.

Future enhancements (not part of this commit) include:
- Implementing a bearing arrow in the MOB navigation view.
- Integrating with a persistent logbook system.

1 files changed, 204 insertions, 1 deletions

diff --git a/android-app/app/src/main/res/layout/activity_main.xml b/android-app/app/src/main/res/layout/activity_main.xml
index 2801f23..3df0645 100644
--- a/android-app/app/src/main/res/layout/activity_main.xml
+++ b/android-app/app/src/main/res/layout/activity_main.xml
@@ -43,7 +43,7 @@
         <androidx.constraintlayout.widget.Guideline
             android:id="@+id/guideline_horizontal_50"
             android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
+            android="layout_height="wrap_content"
             android:orientation="horizontal"
             app:layout_constraintGuide_percent="0.5" />
 
@@ -241,4 +241,207 @@
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintBottom_toBottomOf="parent" />
 
+    <!-- Anchor FAB -->
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+        android:id="@+id/fab_anchor"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="16dp"
+        android:clickable="true"
+        android:focusable="true"
+        android:contentDescription="@string/fab_anchor_content_description"
+        app:srcCompat="@android:drawable/ic_menu_myplaces"
+        app:backgroundTint="@color/anchor_button_background"
+        app:layout_constraintBottom_toTopOf="@+id/fab_mob"
+        app:layout_constraintStart_toStartOf="parent" />
+
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+        android:id="@+id/fab_mob"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="16dp"
+        android:clickable="true"
+        android:focusable="true"
+        android:contentDescription="@string/fab_mob_content_description"
+        app:srcCompat="@android:drawable/ic_dialog_alert"
+        app:backgroundTint="@color/mob_button_background"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintBottom_toBottomOf="parent" />
+
+    <!-- Anchor Configuration Container -->
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/anchor_config_container"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:background="#DD212121"
+        android:padding="16dp"
+        android:visibility="gone"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent">
+
+        <TextView
+            android:id="@+id/anchor_title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/anchor_config_title"
+            android:textColor="@android:color/white"
+            android:textSize="20sp"
+            android:textStyle="bold"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent" />
+
+        <TextView
+            android:id="@+id/anchor_status_text"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="8dp"
+            android:textColor="@android:color/white"
+            android:textSize="16sp"
+            tools:text="Anchor Inactive"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/anchor_title" />
+
+        <LinearLayout
+            android:id="@+id/radius_control_layout"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:orientation="horizontal"
+            android:layout_marginTop="16dp"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/anchor_status_text">
+
+            <Button
+                android:id="@+id/button_decrease_radius"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="-"
+                android:textSize="20sp"
+                android:minWidth="48dp"
+                android:layout_marginEnd="8dp" />
+
+            <TextView
+                android:id="@+id/anchor_radius_text"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:textColor="@android:color/white"
+                android:textSize="18sp"
+                android:textStyle="bold"
+                tools:text="Radius: 50.0m"
+                android:gravity="center_vertical" />
+
+            <Button
+                android:id="@+id/button_increase_radius"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="+"
+                android:textSize="20sp"
+                android:minWidth="48dp"
+                android:layout_marginStart="8dp" />
+
+        </LinearLayout>
+
+        <Button
+            android:id="@+id/button_set_anchor"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="16dp"
+            android:text="@string/button_set_anchor"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/radius_control_layout" />
+
+        <Button
+            android:id="@+id/button_stop_anchor"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="16dp"
+            android:text="@string/button_stop_anchor"
+            android:backgroundTint="@android:color/holo_red_dark"
+            app:layout_constraintStart_toEndOf="@+id/button_set_anchor"
+            app:layout_constraintTop_toBottomOf="@+id/radius_control_layout"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintHorizontal_bias="0.5" />
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+
+    <!-- MOB Navigation Display Container -->
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/mob_navigation_container"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/instrument_background"
+        android:visibility="gone"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent">
+
+        <TextView
+            android:id="@+id/mob_label_distance"
+            style="@style/InstrumentLabel"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/mob_label_distance"
+            app:layout_constraintBottom_toTopOf="@+id/mob_value_distance"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintVertical_chainStyle="packed"
+            app:layout_constraintTop_toTopOf="parent" />
+
+        <TextView
+            android:id="@+id/mob_value_distance"
+            style="@style/InstrumentPrimaryValue"
+            android:layout_width="wrap_content"
+            android://layout_height="wrap_content"
+            tools:text="125 m"
+            android:textSize="80sp"
+            app:layout_constraintBottom_toTopOf="@+id/mob_label_elapsed_time"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/mob_label_distance" />
+
+        <TextView
+            android:id="@+id/mob_label_elapsed_time"
+            style="@style/InstrumentLabel"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="32dp"
+            android:text="@string/mob_label_elapsed_time"
+            app:layout_constraintBottom_toTopOf="@+id/mob_value_elapsed_time"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/mob_value_distance" />
+
+        <TextView
+            android:id="@+id/mob_value_elapsed_time"
+            style="@style/InstrumentPrimaryValue"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            tools:text="00:01:23"
+            android:textSize="60sp"
+            app:layout_constraintBottom_toTopOf="@+id/mob_recovered_button"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/mob_label_elapsed_time" />
+
+        <Button
+            android:id="@+id/mob_recovered_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="64dp"
+            android:text="@string/mob_button_recovered"
+            android:paddingStart="32dp"
+            android:paddingEnd="32dp"
+            android:paddingTop="16dp"
+            android:paddingBottom="16dp"
+            android:textSize="24sp"
+            android:backgroundTint="@color/mob_button_background"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/mob_value_elapsed_time" />
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+
 </androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file