ci: retry pkg-pr-new publish on transient 5xx

[TheodorNEngoy]

The Publish Any Commit workflow uses pkg-pr-new to publish preview packages for each PR.

We’ve seen this step intermittently fail with pkg.pr.new 5xx / Cloudflare worker errors (transient external failures), which blocks otherwise-green PRs.

This change wraps the publish step with a small retry loop:

• Retries up to 3 times with a short backoff.
• Only retries when the output looks like a transient pkg.pr.new/Cloudflare 5xx failure.
• Fails fast on other (likely real) errors.

No behavior changes to the SDK itself.

[changeset-bot]

⚠️ No Changeset found

Latest commit: a8ab7a5

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[pkg-pr-new]

Open in StackBlitz

@modelcontextprotocol/client

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/client@1500

@modelcontextprotocol/server

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/server@1500

@modelcontextprotocol/express

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/express@1500

@modelcontextprotocol/hono

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/hono@1500

@modelcontextprotocol/node

npm i https://pkg.pr.new/modelcontextprotocol/typescript-sdk/@modelcontextprotocol/node@1500

commit: a8ab7a5

[TheodorNEngoy]

Context: this was prompted by transient pkg.pr.new 5xx/Cloudflare errors intermittently failing the required "Publish Any Commit" check (e.g. on #1499). With this retry in place, those flakes should stop blocking otherwise-green PRs.