Loosens lower.zig's `checkRequiredEntryPoints` to accept either a
`#jni_main #jni_class("...")` decl OR the legacy `android_main`
trampoline. The diagnostic now shows both options when neither is
present.
Updates the slice 2 smoke (`examples/ffi-jni-main-01-emit.sx`) to
express the modern shape — drops `android_main`, declares
`Bundle :: #foreign #jni_class("android/os/Bundle")`, and overrides
`onCreate :: (self: *Self, b: *Bundle) { }` inside the #jni_main class.
The emitted Java now correctly declares `void onCreate(Bundle b)` as
@Override + a matching `private native void sx_onCreate(Bundle b)`
delegate, verified via dexdump.
Full retirement of `android_main` (deleting native_app_glue from the
Android link path, dropping `AndroidPlatform.run_frame_loop`, migrating
chess/EGL demo to the Java-driven lifecycle) is multi-slice rework
and stays as follow-up.
Compilation.lowering_jni_main_decls is populated by lowerToIR (iterating
foreign_class_map for is_main && !is_foreign && runtime==jni_class,
deduped by foreign_path); each entry carries the pre-rendered Java source
from jni_java_emit.emitJavaSource.
createApk extended: when the emission list is non-empty, write each
.java under <stage>/java/<pkg>/<Class>.java, javac --release 11 to
<stage>/classes/, d8 --release --lib <android_jar> --output <stage>
to produce <stage>/classes.dex, then zip the .dex into the unaligned
APK at root level. javac discovery: $JAVA_HOME/bin/javac first, then
`which javac`.
Manifest still hardcodes android.app.NativeActivity (slice 3 wires the
user's class name + android:hasCode="true"), so the bundled .dex is
present but unreferenced at runtime. End-to-end verified via dexdump on
the smoke example's APK — Lco/swipelab/sxjnimain/SxApp; extending
NativeActivity shows up in classes.dex. Non-#jni_main APK builds
(99-android-egl-clear.sx) produce the same shape as before.
Cross-compile tuple added for examples/ffi-jni-main-01-emit.sx
(compile-only — APK exercise is manual).
