fix(client): fail fast after SSE reconnect exhaustion

[he-yufeng]

Summary

• raise the default standalone SSE reconnection budget from 2 attempts to 10
• keep track of standalone SSE reconnection exhaustion and fail future request sends instead of letting POSTs succeed while responses are unreachable
• include a fallback HTTP status in SSE-open errors when statusText is empty

Fixes #2098.

To verify

• pnpm --filter @modelcontextprotocol/client test -- streamableHttp.test.ts
• pnpm --filter @modelcontextprotocol/client typecheck
• pnpm --filter @modelcontextprotocol/client lint
• pnpm --filter @modelcontextprotocol/client build
• git diff --check

The pre-push hook also ran repo-wide build/typecheck/lint successfully.

[changeset-bot]

🦋 Changeset detected

Latest commit: 3597345

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@modelcontextprotocol/client	Patch

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commit: 3597345