fix(deploy): fix LATEST_TAG extraction regex and fix bash syntax in install.sh

deploy/upgrade-agent.sh

@@ -38,7 +38,7 @@ case "$ARCH" in
 esac
 
 info "正在获取最新 Release 版本信息..."
-LATEST_TAG=$(curl -fsSL -k "${GITEA_URL}/api/v1/repos/${REPO}/releases/latest" 2>/dev/null | grep '"tag_name":' | head -n1 | sed -E 's/.*"([^"]+)".*/\1/')
+LATEST_TAG=$(curl -fsSL -k "${GITEA_URL}/api/v1/repos/${REPO}/releases/latest" 2>/dev/null | grep -o '"tag_name":"[^"]*"' | head -n1 | cut -d'"' -f4)
 if [ -z "$LATEST_TAG" ]; then
     warn "无法通过 Gitea API 自动获取 Tag，回退至 v1.1.5"
     LATEST_TAG="v1.1.5"