Rename app to EasyView and make APK build cross-platform

- App display name -> EasyView (Android label, PWA manifest, page titles,
  about/guide text, APK artifact name)
- scripts/build-apk.mjs: auto-detect JDK/SDK/Gradle toolchain instead of
  hardcoded Windows paths; pick highest build-tools; platform 34 fallback;
  path.delimiter classpaths; npm run build without cmd.exe on POSIX
- Add build-apk.sh one-shot Linux build wrapper (loads ven env + keystore)
- Signing keystore renamed to easyview.jks (alias easyview),
  env vars EASYVIEW_KEYSTORE_PASS / EASYVIEW_KEY_PASS

build-apk.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# 一键构建 EasyView APK（Linux / 本工作区 ven 工具链）
+# 用法：./build-apk.sh
+set -euo pipefail
+
+here="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ven="$(cd "$here/../ven" && pwd)"
+
+source "$ven/node-env.sh"
+export npm_config_cache="$ven/npm"
+export ANDROID_HOME="$ven/android-sdk"
+export ANDROID_SDK_ROOT="$ANDROID_HOME"
+
+# 签名口令：优先取 android/keystore/.env.keystore（已 gitignore）
+if [[ -f "$here/android/keystore/.env.keystore" ]]; then
+  set -a
+  # shellcheck disable=SC1091
+  . "$here/android/keystore/.env.keystore"
+  set +a
+fi
+: "${EASYVIEW_KEYSTORE_PASS:?未设置签名口令：请在 android/keystore/.env.keystore 中写入 EASYVIEW_KEYSTORE_PASS}"
+
+cd "$here"
+node scripts/build-apk.mjs