feat: refactor UI to BottomNavigationView with Safety and Doc fragments

Replace FAB-based navigation with a 4-tab BottomNavigationView (Map,
Instruments, Log, Safety). Instruments use a collapsible bottom sheet;
Log and Safety display as full-screen overlay fragments.

- Add SafetyFragment with MOB and Anchor Watch controls
- Add DocFragment for in-app markdown help (Markwon: core, tables, images)
- Add layout_instruments_sheet with 3x3 instrument grid and PolarDiagramView
- Add fragment_safety and fragment_doc layouts
- Add vector drawables: ic_map, ic_instruments, ic_log, ic_safety, ic_close
- Update activity_main.xml to CoordinatorLayout with bottom sheet + overlay
- Fix: set isHideable=true before STATE_HIDDEN to avoid silent no-op from
  behavior_hideable=false default; restore false on Map/Instruments tabs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/android-app/app/src/main/res/layout/fragment_safety.xml b/android-app/app/src/main/res/layout/fragment_safety.xml
new file mode 100644
index 0000000..5b2397e
--- /dev/null
+++ b/android-app/app/src/main/res/layout/fragment_safety.xml
@@ -0,0 +1,107 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:padding="24dp"
+    android:background="?attr/colorSurface">
+
+    <TextView
+        android:id="@+id/safety_title"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Safety Dashboard"
+        android:textSize="24sp"
+        android:textStyle="bold"
+        android:textColor="?attr/colorOnSurface"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintStart_toStartOf="parent" />
+
+    <com.google.android.material.button.MaterialButton
+        android:id="@+id/button_help_safety"
+        style="@style/Widget.Material3.Button.TextButton"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="HELP"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintEnd_toEndOf="parent" />
+
+    <!-- MOB Section -->
+    <com.google.android.material.card.MaterialCardView
+        android:id="@+id/card_mob"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="24dp"
+        app:cardCornerRadius="16dp"
+        app:layout_constraintTop_toBottomOf="@id/safety_title">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="16dp"
+            android:gravity="center">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="MAN OVERBOARD"
+                android:textColor="@color/md_theme_error"
+                android:textStyle="bold" />
+
+            <com.google.android.material.button.MaterialButton
+                android:id="@+id/button_mob_activate"
+                android:layout_width="match_parent"
+                android:layout_height="80dp"
+                android:layout_marginTop="16dp"
+                android:text="ACTIVATE MOB"
+                android:textSize="20sp"
+                app:backgroundTint="@color/md_theme_error" />
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+    <!-- Anchor Section -->
+    <com.google.android.material.card.MaterialCardView
+        android:id="@+id/card_anchor"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="16dp"
+        app:cardCornerRadius="16dp"
+        app:layout_constraintTop_toBottomOf="@id/card_mob">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="16dp">
+
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="ANCHOR WATCH"
+                android:textStyle="bold" />
+
+            <TextView
+                android:id="@+id/anchor_status_summary"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:text="Status: Inactive"
+                android:textColor="?attr/colorOnSurfaceVariant" />
+
+            <com.google.android.material.button.MaterialButton
+                android:id="@+id/button_anchor_config"
+                style="@style/Widget.Material3.Button.TonalButton"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="16dp"
+                android:text="CONFIGURE ANCHOR WATCH" />
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+</androidx.constraintlayout.widget.ConstraintLayout>