ci(android): replace cargo-apk with cargo-ndk + manual APK assembly

cargo-apk 0.10 and its fork cargo-apk2 both failed to discover the
installed Android platform in this Gitea runner, despite ANDROID_HOME,
platforms;android-34, build-tools, and NDK all being present, readable,
and pointed at correctly. We never isolated whether the bug is in the
shared ndk-build crate's discovery logic or in the runner's env-var
propagation through cargo subcommand exec, so this commit stops fighting
either tool and assembles the APK from explicit toolchain steps instead:

  cargo ndk          -> per-ABI .so files
  aapt2 compile/link -> manifest + resources -> base APK
  zip                -> bundle native libs into lib/<abi>/
  zipalign           -> 4-byte alignment
  apksigner          -> v2/v3 signing (debug keystore for CI, real for release)

The pipeline lives in scripts/build_android_apk.sh so it's reproducible
locally (same env vars, same commands). AndroidManifest.xml is now
checked in under solitaire_app/android/ and mirrors what cargo-apk would
have generated from [package.metadata.android] — keep them in sync if
either is changed. Local `cargo apk build` still works on developer
machines where cargo-apk is happy; CI just stops depending on it.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/build_android_apk.sh

@@ -0,0 +1,135 @@
+#!/usr/bin/env bash
+# Build a self-signed Android APK from solitaire_app's cdylib targets.
+#
+# Replaces the cargo-apk pipeline with explicit cargo-ndk + aapt2 + apksigner
+# steps. The CI runner was hitting an SDK-discovery bug inside cargo-apk's
+# ndk-build crate that we couldn't isolate; running each Android toolchain
+# step explicitly gives us a debuggable pipeline.
+#
+# Required environment:
+#   ANDROID_HOME            Path to Android SDK root
+#   ANDROID_NDK_HOME        Path to the specific NDK version
+#   BUILD_TOOLS_VERSION     e.g. "34.0.0"
+#   PLATFORM                e.g. "android-34"
+#
+# Optional environment:
+#   PROFILE                 "debug" (default) | "release"
+#   APK_OUT                 Output APK path (default: target/$PROFILE/apk/solitaire-quest.apk)
+#   KEYSTORE                Path to keystore for signing (default: generates a debug keystore)
+#   KEYSTORE_PASS           Keystore password (default: "android" for the generated debug keystore)
+#   KEY_ALIAS               Key alias (default: "androiddebugkey")
+#   KEY_PASS                Key password (default: same as KEYSTORE_PASS)
+#
+# Outputs:
+#   $APK_OUT                Signed, zipaligned APK
+set -euo pipefail
+
+: "${ANDROID_HOME:?ANDROID_HOME must be set}"
+: "${ANDROID_NDK_HOME:?ANDROID_NDK_HOME must be set}"
+: "${BUILD_TOOLS_VERSION:?BUILD_TOOLS_VERSION must be set}"
+: "${PLATFORM:?PLATFORM must be set (e.g. android-34)}"
+
+PROFILE="${PROFILE:-debug}"
+APK_OUT="${APK_OUT:-target/${PROFILE}/apk/solitaire-quest.apk}"
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$REPO_ROOT"
+
+BT="$ANDROID_HOME/build-tools/$BUILD_TOOLS_VERSION"
+PLATFORM_JAR="$ANDROID_HOME/platforms/$PLATFORM/android.jar"
+MANIFEST="solitaire_app/android/AndroidManifest.xml"
+RES_DIR="solitaire_app/res"
+ASSETS_DIR="assets"
+
+# --- sanity ----------------------------------------------------------------
+for f in "$BT/aapt2" "$BT/zipalign" "$BT/apksigner" "$PLATFORM_JAR" "$MANIFEST"; do
+  [ -e "$f" ] || { echo "missing: $f"; exit 1; }
+done
+
+STAGING="$(mktemp -d)"
+trap 'rm -rf "$STAGING"' EXIT
+mkdir -p "$STAGING/lib" "$STAGING/compiled-res"
+
+# --- 1. native libraries via cargo-ndk -------------------------------------
+# `-o $STAGING/lib` lays out files as $STAGING/lib/<abi>/libsolitaire_app.so
+# which is the directory structure the APK expects under lib/.
+CARGO_NDK_ARGS=(
+  -t arm64-v8a
+  -t armeabi-v7a
+  -t x86_64
+  --platform 26
+  -o "$STAGING/lib"
+  build --package solitaire_app --lib
+)
+if [ "$PROFILE" = "release" ]; then
+  CARGO_NDK_ARGS+=( --release )
+fi
+echo ">>> cargo ndk ${CARGO_NDK_ARGS[*]}"
+cargo ndk "${CARGO_NDK_ARGS[@]}"
+
+# --- 2. compile + link resources and manifest ------------------------------
+if [ -d "$RES_DIR" ]; then
+  echo ">>> aapt2 compile resources"
+  "$BT/aapt2" compile --dir "$RES_DIR" -o "$STAGING/compiled-res"
+fi
+
+LINK_ARGS=(
+  link
+  -o "$STAGING/app-unsigned.apk"
+  -I "$PLATFORM_JAR"
+  --manifest "$MANIFEST"
+)
+[ -d "$ASSETS_DIR" ] && LINK_ARGS+=( -A "$ASSETS_DIR" )
+# Add compiled resources if any
+shopt -s nullglob
+RES_FLATS=( "$STAGING/compiled-res"/*.flat )
+shopt -u nullglob
+if [ ${#RES_FLATS[@]} -gt 0 ]; then
+  LINK_ARGS+=( "${RES_FLATS[@]}" )
+fi
+echo ">>> aapt2 link"
+"$BT/aapt2" "${LINK_ARGS[@]}"
+
+# --- 3. add native libraries to the APK ------------------------------------
+echo ">>> bundle native libraries"
+( cd "$STAGING" && zip -r -q app-unsigned.apk lib/ )
+
+# --- 4. zipalign -----------------------------------------------------------
+echo ">>> zipalign"
+"$BT/zipalign" -p -f 4 "$STAGING/app-unsigned.apk" "$STAGING/app-aligned.apk"
+
+# --- 5. sign ---------------------------------------------------------------
+if [ -z "${KEYSTORE:-}" ]; then
+  # Generate a deterministic debug keystore on the fly.
+  KEYSTORE="$STAGING/debug.keystore"
+  KEYSTORE_PASS="${KEYSTORE_PASS:-android}"
+  KEY_ALIAS="${KEY_ALIAS:-androiddebugkey}"
+  KEY_PASS="${KEY_PASS:-$KEYSTORE_PASS}"
+  echo ">>> generating debug keystore at $KEYSTORE"
+  keytool -genkeypair -v \
+    -keystore "$KEYSTORE" \
+    -storepass "$KEYSTORE_PASS" \
+    -alias "$KEY_ALIAS" \
+    -keypass "$KEY_PASS" \
+    -keyalg RSA -keysize 2048 -validity 10000 \
+    -dname "CN=Android Debug,O=Android,C=US" > /dev/null
+fi
+
+KEYSTORE_PASS="${KEYSTORE_PASS:-android}"
+KEY_ALIAS="${KEY_ALIAS:-androiddebugkey}"
+KEY_PASS="${KEY_PASS:-$KEYSTORE_PASS}"
+
+mkdir -p "$(dirname "$APK_OUT")"
+echo ">>> apksigner sign -> $APK_OUT"
+"$BT/apksigner" sign \
+  --ks "$KEYSTORE" \
+  --ks-pass "pass:$KEYSTORE_PASS" \
+  --ks-key-alias "$KEY_ALIAS" \
+  --key-pass "pass:$KEY_PASS" \
+  --out "$APK_OUT" \
+  "$STAGING/app-aligned.apk"
+
+echo ">>> verify"
+"$BT/apksigner" verify --verbose "$APK_OUT"
+
+echo ">>> done: $APK_OUT"