refactor(drone): improve PM2 command handling in deployment script

- Replaced direct PM2 commands with a function to check for PM2 or npx availability, enhancing error handling and flexibility.
- Updated the deployment script in .drone.yml to set the PATH correctly, ensuring that npm global binaries are accessible.
- This refactor streamlines the application lifecycle management for the nuxt4-demo, improving the robustness of the deployment process.

.drone.yml

@@ -67,6 +67,25 @@ steps:
         rm -rf "$UNZIP_DIR"
         mkdir -p "$UNZIP_DIR"
         tar -xzf "$REPO_DIR/build-output.tar.gz" -C "$UNZIP_DIR"
-      - 'bash -lc "cd $UNZIP_DIR && pm2 stop nuxt4-demo || true"'
-      - 'bash -lc "cd $UNZIP_DIR && pm2 delete nuxt4-demo || true"'
-      - 'bash -lc "cd $UNZIP_DIR && pm2 start ./run.sh --name nuxt4-demo"'
+      - |
+        set -e
+        cd "$UNZIP_DIR"
+        # exec runner 常缺登录 PATH，补 npm 全局 bin（pm2 多装在这里）
+        if command -v npm >/dev/null 2>&1; then
+          _pfx="$(npm config get prefix 2>/dev/null || true)"
+          case "$_pfx" in /*) export PATH="${_pfx}/bin:${PATH}" ;; esac
+        fi
+        export PATH="${HOME}/.bun/bin:/usr/local/bin:/usr/bin:${PATH}"
+        run_pm2() {
+          if command -v pm2 >/dev/null 2>&1; then
+            command pm2 "$@"
+          elif command -v npx >/dev/null 2>&1; then
+            npx --yes pm2 "$@"
+          else
+            echo "未找到 pm2 且没有 npx，请在 Runner 上执行: npm i -g pm2"
+            exit 1
+          fi
+        }
+        run_pm2 stop nuxt4-demo || true
+        run_pm2 delete nuxt4-demo || true
+        run_pm2 start ./run.sh --name nuxt4-demo