Minamp 1.6: adjustable UI size, larger text and controls

- New setting "Text and button size" (Normal / Large / Extra large): scales
  text, icons and buttons on top of the phone's density (App.UI_SCALES)
- Larger default text, rows, tiles, touch targets and player icons; all sizes
  now live in res/values/dimens.xml
- Seek bar knob drawn in code, since Android 2.x caches XML shapes at the
  size they were first loaded
- Full-width buttons wrap to two lines instead of cutting words off
- Shorter labels so they fit 240x320 screens in both languages
- tools/check_fit.py checks that UI texts fit their slots at every size and
  language using Droid Sans metrics; build.sh runs it and setup_toolchain.sh
  fetches the font

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

res/layout/view_topbar.xml

@@ -2,7 +2,7 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/topbar"
     android:layout_width="match_parent"
-    android:layout_height="46dp"
+    android:layout_height="@dimen/topbar"
     android:orientation="horizontal"
     android:gravity="center_vertical"
     android:paddingLeft="4dp"
@@ -20,7 +20,7 @@
             android:layout_width="match_parent" android:layout_height="wrap_content" />
         <TextView android:id="@+id/bar_sub" style="@style/Sub"
             android:layout_width="match_parent" android:layout_height="wrap_content"
-            android:textSize="11sp" android:visibility="gone" />
+            android:textSize="@dimen/text_small" android:visibility="gone" />
     </LinearLayout>
 
     <ImageButton android:id="@+id/btn_action" style="@style/IconButton" android:visibility="gone" />