App 2.16.4: drop-downs that keep full screen

Back to drop-downs for upload frequency, tyre pressure unit and accent
colour, as Material exposed dropdown menus instead of Spinners. A
Spinner's list is a focusable window of its own without the
full-screen flags, so the car showed its bars while it was open; an
exposed dropdown's list leaves the focus with the activity, so the app
stays full screen. Styled like the other input fields, with full-height
rows. Replaces the buttons of 2.16.3.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QLJfZQZeAKAwSqViTmLzki

app/src/main/res/values/styles_app.xml

@@ -43,6 +43,19 @@
     <item name="endIconTint">@color/ev_text_secondary</item>
     <item name="helperTextTextAppearance">@style/Text.EV.Secondary</item>
   </style>
+  <!-- A drop-down that keeps the app full screen: an exposed dropdown menu's list does not take
+       focus from the activity's window, unlike a Spinner's, so the car's bars stay hidden. -->
+  <style name="Widget.EV.Dropdown" parent="Widget.Material3.TextInputLayout.OutlinedBox.ExposedDropdownMenu">
+    <item name="boxBackgroundColor">@color/ev_background</item>
+    <item name="boxStrokeColor">@color/input_stroke</item>
+    <item name="boxStrokeWidth">1dp</item>
+    <item name="boxStrokeWidthFocused">2dp</item>
+    <item name="boxCornerRadiusTopStart">16dp</item>
+    <item name="boxCornerRadiusTopEnd">16dp</item>
+    <item name="boxCornerRadiusBottomStart">16dp</item>
+    <item name="boxCornerRadiusBottomEnd">16dp</item>
+    <item name="endIconTint">?attr/evAccent</item>
+  </style>
   <style name="Text.EV.Eyebrow" parent="Text.EV.SectionHeader">
     <item name="android:textSize">16sp</item>
     <item name="android:textColor">?attr/evAccent</item>