android: package only the ABIs we actually build for

The first working APK carried libjnidispatch.so for armeabi, mips and mips64 as
well as our four — JNA's .aar still ships those, and AGP packages whatever it
finds. Android dropped mips in NDK r17 and armeabi in r17 too; nothing that can
install this app can load them, so they are pure payload.

abiFilters pins the set to the four the Rust is actually cross-compiled for, so
the APK's ABI list matches the build's intent rather than the union of every
dependency's history.

Found by unpacking the artifact rather than trusting the green: the run said
"Upload debug APK ✓", which is true and says nothing about what is inside it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

android/app/build.gradle.kts

@@ -162,6 +162,16 @@ android {
             (project.findProperty("THOUGHTSYNC_VERSION_CODE") as String?)?.toIntOrNull()
         versionCode = codeOverride ?: 1
         versionName = nameOverride ?: "dev"
+
+        // Package ONLY the ABIs we build for.
+        //
+        // Without this the APK also carries armeabi, mips and mips64 — dead
+        // architectures Android dropped years ago, which arrive because JNA's
+        // .aar still ships a libjnidispatch.so for each. They can never be
+        // loaded on any device this app supports, so they are pure payload.
+        ndk {
+            abiFilters += androidAbis
+        }
     }
 
     buildTypes {