fix: Windows encoding (UTF-8 BOM + CRLF) and macOS Gatekeeper

- Windows bat files: UTF-8 BOM + CRLF + English text to avoid garbled Chinese in cmd.exe
- macOS scripts: xattr -rd com.apple.quarantine to fix "unverified developer" popup
- New install scripts: Mac-安装并启动.command, Windows-安装并启动.bat
  (extract tar.gz to local disk then launch)

uclaw-scripts/Mac-从U盘启动.command

@@ -92,6 +92,14 @@ export OPENCLAW_CONFIG_PATH="$PORTABLE_CONFIG_PATH"
 
 mkdir -p "$PORTABLE_STATE_DIR"
 
+# 移除 macOS 隔离标记（解决"无法验证开发者"弹窗）
+if xattr -l "$NODE_BIN" 2>/dev/null | grep -q "com.apple.quarantine"; then
+    echo -e "  ${YELLOW}正在移除 macOS 安全限制...${NC}"
+    xattr -rd com.apple.quarantine "$UCLAW_DIR" 2>/dev/null || true
+    echo -e "  ${GREEN}已移除${NC}"
+    echo ""
+fi
+
 # 检查依赖
 if [ ! -d "$OPENCLAW_DIR/node_modules" ]; then
     echo -e "  ${YELLOW}首次运行，正在安装依赖...${NC}"