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>

5 files changed, 46 insertions, 0 deletions

diff --git a/android-app/app/src/main/res/drawable/ic_close.xml b/android-app/app/src/main/res/drawable/ic_close.xml
new file mode 100644
index 0000000..16d6d37
--- /dev/null
+++ b/android-app/app/src/main/res/drawable/ic_close.xml
@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorControlNormal">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M19,6.41L17.59,5 12,10.59 6.41,5 5,6.41 10.59,12 5,17.59 6.41,19 12,13.41 17.59,19 19,17.59 13.41,12z"/>
+</vector>
diff --git a/android-app/app/src/main/res/drawable/ic_instruments.xml b/android-app/app/src/main/res/drawable/ic_instruments.xml
new file mode 100644
index 0000000..9ba6fad
--- /dev/null
+++ b/android-app/app/src/main/res/drawable/ic_instruments.xml
@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM12,20c-4.41,0 -8,-3.59 -8,-8s3.59,-8 8,-8 8,3.59 8,8 -3.59,8 -8,8zM12.5,7h-1v6l5.25,3.15 0.75,-1.23 -4.5,-2.67z"/>
+</vector>
diff --git a/android-app/app/src/main/res/drawable/ic_log.xml b/android-app/app/src/main/res/drawable/ic_log.xml
new file mode 100644
index 0000000..cd3a27c
--- /dev/null
+++ b/android-app/app/src/main/res/drawable/ic_log.xml
@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M14,2H6C4.9,2 4.01,2.9 4.01,4L4,20c0,1.1 0.89,2 1.99,2H18c1.1,0 2,-0.9 2,-2V8l-6,-6zM18,20H6V4h7v5h5v11z"/>
+</vector>
diff --git a/android-app/app/src/main/res/drawable/ic_map.xml b/android-app/app/src/main/res/drawable/ic_map.xml
new file mode 100644
index 0000000..d17e9cd
--- /dev/null
+++ b/android-app/app/src/main/res/drawable/ic_map.xml
@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M20.5,3l-0.16,0.03L15,5.1 9,3 3.36,4.9c-0.21,0.07 -0.36,0.25 -0.36,0.48V20.5c0,0.28 0.22,0.5 0.5,0.5l0.16,-0.03L9,18.9l6,2.1 5.64,-1.9c0.21,-0.07 0.36,-0.25 0.36,-0.48V3.5c0,-0.28 -0.22,-0.5 -0.5,-0.5zM15,19l-6,-2.11V5l6,2.11V19z"/>
+</vector>
diff --git a/android-app/app/src/main/res/drawable/ic_safety.xml b/android-app/app/src/main/res/drawable/ic_safety.xml
new file mode 100644
index 0000000..8d4477d
--- /dev/null
+++ b/android-app/app/src/main/res/drawable/ic_safety.xml
@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M12,1L3,5v6c0,5.55 3.84,10.74 9,12 5.16,-1.26 9,-6.45 9,-12V5l-9,-4zM12,11.99h7c-0.53,4.12 -3.28,7.79 -7,8.94V12H5V6.3l7,-3.11v8.8z"/>
+</vector>