ci: verify split apk version code

Jenkinsfile

@@ -59,7 +59,10 @@ pipeline {
                     if (versionParts.size() != 2) { error("Invalid pubspec version: ${env.PUBSPEC_VERSION}") }
                     env.APP_VERSION = versionParts[0]
                     env.BASE_VERSION_CODE = versionParts[1]
-                    env.ANDROID_VERSION_CODE = "${versionParts[1].toInteger() + env.BUILD_NUMBER.toInteger()}"
+                    env.FLUTTER_BUILD_NUMBER = "${versionParts[1].toInteger() + env.BUILD_NUMBER.toInteger()}"
+                    // Flutter's split-per-abi Gradle configuration assigns arm64-v8a
+                    // the 2xxx versionCode range while preserving the build-number suffix.
+                    env.ANDROID_VERSION_CODE = "${env.FLUTTER_BUILD_NUMBER.toInteger() + 2000}"
                     env.SHORT_SHA = sh(script: 'git rev-parse --short=8 HEAD', returnStdout: true).trim()
                     env.IMMUTABLE_TAG = "${env.APP_VERSION}-internal-b${env.BUILD_NUMBER}-${env.SHORT_SHA}"
                     env.APK_BASENAME = "JiZhi-${env.IMMUTABLE_TAG}-vc${env.ANDROID_VERSION_CODE}-arm64-v8a.apk"
@@ -165,7 +168,7 @@ PY
                             set -euo pipefail
                             "$FLUTTER_ROOT/bin/flutter" build apk \
                               --flavor internal --release --target-platform android-arm64 --split-per-abi \
-                              --build-name "$APP_VERSION" --build-number "$ANDROID_VERSION_CODE" \
+                              --build-name "$APP_VERSION" --build-number "$FLUTTER_BUILD_NUMBER" \
                               --dart-define=INTERNAL_BUILD=true \
                               --dart-define="API_BASE_URL=$API_BASE_URL" \
                               --dart-define="APP_VERSION=$IMMUTABLE_TAG"