fix(ui): layer previews, fishing pole icon, button alignment, safety page cleanup

- Layer picker: change android:src→android:background on preview ImageViews; shape
  drawables have no intrinsic size so centerCrop renders blank — background fills correctly
- Replace ic_fish with ic_fishing_pole (rod + reel + line + hook vector)
- Move fab_fishing to CoordinatorLayout with layout_anchor on instrument_bottom_sheet
  top|start, matching fab_record_track positioning so both FABs sit level at sheet top
- Raise fishing_overlay marginBottom 140dp→200dp to clear the realigned FAB
- Safety: remove HELP button + DocFragment import from SafetyFragment; rename Quit→Quit App

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

3 files changed, 28 insertions, 48 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 a1939c1..fc60c80 100644
--- a/android-app/app/src/main/res/layout/activity_main.xml
+++ b/android-app/app/src/main/res/layout/activity_main.xml
@@ -95,24 +95,11 @@
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_marginStart="8dp"
-                android:layout_marginBottom="140dp"
+                android:layout_marginBottom="200dp"
                 android:visibility="gone"
                 app:layout_constraintBottom_toBottomOf="parent"
                 app:layout_constraintStart_toStartOf="parent" />
 
-            <!-- Fishing mode FAB — bottom-start -->
-            <com.google.android.material.floatingactionbutton.FloatingActionButton
-                android:id="@+id/fab_fishing"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:layout_marginStart="16dp"
-                android:layout_marginBottom="136dp"
-                android:src="@drawable/ic_fish"
-                android:contentDescription="Fishing mode"
-                app:fabSize="mini"
-                app:elevation="8dp"
-                app:layout_constraintBottom_toBottomOf="parent"
-                app:layout_constraintStart_toStartOf="parent" />
 
             <com.google.android.material.button.MaterialButton
                 android:id="@+id/fab_recenter"
@@ -169,6 +156,19 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintEnd_toEndOf="parent" />
 
+        <!-- Fishing mode FAB — anchored to sheet top-start, vertically aligned with record track -->
+        <com.google.android.material.floatingactionbutton.FloatingActionButton
+            android:id="@+id/fab_fishing"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_margin="16dp"
+            android:src="@drawable/ic_fishing_pole"
+            android:contentDescription="Fishing mode"
+            app:fabSize="mini"
+            app:elevation="20dp"
+            app:layout_anchor="@id/instrument_bottom_sheet"
+            app:layout_anchorGravity="top|start" />
+
         <!-- Record Track Button -->
         <com.google.android.material.floatingactionbutton.FloatingActionButton
             android:id="@+id/fab_record_track"
diff --git a/android-app/app/src/main/res/layout/fragment_safety.xml b/android-app/app/src/main/res/layout/fragment_safety.xml
index 420ccef..2c06431 100644
--- a/android-app/app/src/main/res/layout/fragment_safety.xml
+++ b/android-app/app/src/main/res/layout/fragment_safety.xml
@@ -34,17 +34,10 @@
                 style="@style/Widget.Material3.Button.TextButton"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:text="Quit"
+                android:text="Quit App"
                 android:textColor="?attr/colorOnSurfaceVariant"
                 app:icon="@drawable/ic_close" />
 
-            <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" />
-
         </LinearLayout>
 
         <!-- MOB Section -->
diff --git a/android-app/app/src/main/res/layout/layout_layer_picker_sheet.xml b/android-app/app/src/main/res/layout/layout_layer_picker_sheet.xml
index cba4be1..ce52108 100644
--- a/android-app/app/src/main/res/layout/layout_layer_picker_sheet.xml
+++ b/android-app/app/src/main/res/layout/layout_layer_picker_sheet.xml
@@ -61,8 +61,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="80dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_ocean"
+                        android:background="@drawable/preview_ocean"
                         android:contentDescription="Ocean base map preview"/>
                     <TextView
                         android:layout_width="match_parent"
@@ -92,8 +91,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="80dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_satellite"
+                        android:background="@drawable/preview_satellite"
                         android:contentDescription="Satellite base map preview"/>
                     <TextView
                         android:layout_width="match_parent"
@@ -123,8 +121,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="80dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_charts"
+                        android:background="@drawable/preview_charts"
                         android:contentDescription="Charts base map preview"/>
                     <TextView
                         android:layout_width="match_parent"
@@ -154,8 +151,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="80dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_hybrid"
+                        android:background="@drawable/preview_hybrid"
                         android:contentDescription="Hybrid base map preview"/>
                     <TextView
                         android:layout_width="match_parent"
@@ -211,8 +207,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_seamarks"
+                        android:background="@drawable/preview_seamarks"
                         android:contentDescription="Seamarks preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_seamarks"
@@ -241,8 +236,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_ocean"
+                        android:background="@drawable/preview_ocean"
                         android:contentDescription="ATON preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_aton"
@@ -271,8 +265,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_charts"
+                        android:background="@drawable/preview_charts"
                         android:contentDescription="TSS preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_tss"
@@ -326,8 +319,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_depth"
+                        android:background="@drawable/preview_depth"
                         android:contentDescription="Depth preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_depth"
@@ -356,8 +348,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_sst"
+                        android:background="@drawable/preview_sst"
                         android:contentDescription="SST preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_sst"
@@ -386,8 +377,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_ocean"
+                        android:background="@drawable/preview_ocean"
                         android:contentDescription="FADs preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_fads"
@@ -441,8 +431,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_wind"
+                        android:background="@drawable/preview_wind"
                         android:contentDescription="Wind preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_wind"
@@ -471,8 +460,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_wind"
+                        android:background="@drawable/preview_wind"
                         android:contentDescription="Particles preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_particles"
@@ -526,8 +514,7 @@
                     <ImageView
                         android:layout_width="match_parent"
                         android:layout_height="48dp"
-                        android:scaleType="centerCrop"
-                        android:src="@drawable/preview_satellite"
+                        android:background="@drawable/preview_satellite"
                         android:contentDescription="Past tracks preview"/>
                     <com.google.android.material.switchmaterial.SwitchMaterial
                         android:id="@+id/switch_past_tracks"