Bump AGP to 8.5.2 and Gradle to 8.7 for 16 KB page-size support

Every .so this project builds was already ELF-segment-aligned for 16 KB
pages (build-image/Dockerfile's ANDROID_16KB_LDFLAGS, app/build.gradle's
own CMAKE_SHARED_LINKER_FLAGS), but AGP 8.1.1 doesn't align native
libraries' zip entries within the APK itself - that only became automatic
in AGP 8.5.1, which is what Android Studio's "not compatible with 16 KB
devices" warning was actually flagging. No build-image changes needed:
Gradle/AGP are resolved over the network at build time, not baked into
the image.

android/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,7 @@
-#Thu Nov 11 18:20:34 PST 2021
+#Sat Sep 05 16:12:16 CEST 2026
 distributionBase=GRADLE_USER_HOME
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
 distributionPath=wrapper/dists
-zipStorePath=wrapper/dists
+distributionSha256Sum=544c35d6bd849ae8a5ed0bcea39ba677dc40f49df7d1835561582da2009b961d
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
 zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists