fix(build): build-tauri-android.sh — copy libc++_shared.so into jniLibs

Root cause of "wzp-native not loaded" at runtime on opus-DRED-v2 APK:

libwzp_native.so has a NEEDED entry for libc++_shared.so (because
crates/wzp-native/build.rs uses cpp_link_stdlib(Some("c++_shared"))),
but the APK only contained:
    lib/arm64-v8a/libwzp_desktop_lib.so  (192 MB)
    lib/arm64-v8a/libwzp_native.so       (683 KB)

No libc++_shared.so → Android's dynamic linker fails the dlopen of
libwzp_native.so at runtime with "library libc++_shared.so not found",
and every audio path that routes through wzp_native (capture, playout,
register, direct call) refuses to start.

Diagnosis:
- readelf -d libwzp_native.so shows NEEDED libc++_shared.so
- python zipfile listing of the APK confirms libc++_shared.so is
  absent from lib/arm64-v8a/
- scripts/build-and-notify.sh (the legacy wzp-android build path)
  already had this fix at lines 126-134 with an explicit comment:
  "cargo-ndk may not copy libc++_shared.so — grab it from the NDK if
  missing". That fix was never ported to build-tauri-android.sh when
  the Tauri mobile pipeline was set up.

Fix: after `cargo ndk build -p wzp-native --release` produces
libwzp_native.so into jniLibs, copy libc++_shared.so from the NDK
sysroot (same find pattern as build-and-notify.sh) into the same
jniLibs dir. Abort with a clear error if the NDK doesn't have the file.

Also noting the 191 MB vs 359 MB size discrepancy the user saw: that's
almost entirely libwzp_desktop_lib.so being a 192 MB debug build. The
old working APK was probably a release build (smaller main lib) or
included multiple arches (doubling/tripling the .so count). The size
is cosmetic — the crash is the real issue, and libc++_shared.so is
~2 MB so this fix doesn't close the size gap. Can investigate the
size difference separately after register + direct call work again.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/build-tauri-android.sh

@@ -199,6 +199,26 @@ else
     echo ">>> WARNING: libwzp_native.so not produced"
 fi
 
+# ─── libc++_shared.so — required by wzp-native at runtime ──────────────
+# wzp-native/build.rs uses cpp_link_stdlib(Some("c++_shared")) which adds
+# a NEEDED entry for libc++_shared.so to libwzp_native.so. cargo-ndk does
+# NOT copy the actual libc++_shared.so into jniLibs, so unless we copy it
+# explicitly, the APK ships without it and Android's dynamic linker fails
+# the dlopen with "library libc++_shared.so not found" at runtime. Same
+# fix that build-and-notify.sh has had for the legacy wzp-android path
+# (lines 126-134 there) — ported here for the Tauri pipeline.
+if [ ! -f "$JNI_ABI_DIR/libc++_shared.so" ]; then
+    echo ">>> libc++_shared.so missing, copying from NDK..."
+    NDK_LIBCXX=$(find "$ANDROID_NDK_HOME" -name "libc++_shared.so" -path "*/aarch64-linux-android/*" | head -1)
+    if [ -n "$NDK_LIBCXX" ]; then
+        cp "$NDK_LIBCXX" "$JNI_ABI_DIR/"
+        ls -lh "$JNI_ABI_DIR/libc++_shared.so"
+    else
+        echo ">>> ERROR: libc++_shared.so not found in NDK — APK will crash at dlopen time"
+        exit 1
+    fi
+fi
+
 echo ">>> cargo tauri android build ${PROFILE_FLAG} --target aarch64 --apk"
 cargo tauri android build ${PROFILE_FLAG} --target aarch64 --apk