build: update Android NDK to r30 (30.0.14904198)

clients/android/README.md

@@ -32,7 +32,7 @@ clients/android/                   Gradle project (this dir)
 
 ## Prerequisites (already set up on the dev Mac)
 
-- Android SDK + **NDK r28 LTS** (`28.2.13676358`), `platforms;android-37.0`, `build-tools;37.0.0`
+- Android SDK + **NDK r30** (`30.0.14904198`), `platforms;android-37.0`, `build-tools;37.0.0`
 - **JDK 21** for Gradle/AGP (the machine default JDK 25 is too new for AGP 9.2)
 - Rust + `rustup target add aarch64-linux-android x86_64-linux-android` + `cargo install cargo-ndk`
 

clients/android/kit/build.gradle.kts

@@ -7,7 +7,7 @@ plugins {
     id("com.android.library")
 }
 
-val ndkVer = "28.2.13676358" // r28 LTS — matches the SDK NDK installed for cargo-ndk
+val ndkVer = "30.0.14904198" // r30-beta1 — matches the SDK NDK installed for cargo-ndk
 
 android {
     namespace = "io.unom.punktfunk.kit"