fix: add adaptive icon to remove launcher ring effect on Pixel devices

Without mipmap-anydpi-v26 XML, Pixel launcher wraps legacy PNGs in a
white ring template. Adding adaptive-icon XML with the iOS-matching
foreground PNG at correct per-density sizes (108dp canvas) eliminates
the nested-ring appearance.

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

app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@android:color/transparent"/>
+    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+</adaptive-icon>

app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@android:color/transparent"/>
+    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+</adaptive-icon>