refactor(render): deduplicate code

[gabrielmfern]

this makes sure we don't fix a portion of the code but still have some other place that's broken

---

Summary by cubic

Deduplicates the render pipeline and unifies stream decoding across environments, fixing multi‑byte character issues and making error handling consistent. This reduces repeated code in browser, edge, and node paths.

• Refactors

  • Introduced shared renderToReadableStream and used it in browser, edge, and node where supported.
  • Unified stream reading with a streaming TextDecoder; simplified Node readStream to PipeableStream only.
  • Added browser read-stream tests and updated existing tests.
  • tsconfig now includes node and vitest/globals types; added @types/node dev dependency.

• Bug Fixes

  • Correctly decodes multi-byte characters (CJK, emoji) split across chunks.
  • Improved Node render error propagation by handling onShellError.

^{Written for commit 2139b56. Summary will update automatically on new commits.}

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Latest commit: 2139b56

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Project	Deployment	Review	Updated (UTC)
react-email	Ready	Preview, Comment	Dec 18, 2025 2:45pm
react-email-demo	Ready	Preview, Comment	Dec 18, 2025 2:45pm

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Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​types/​node@​24.9.1 ⏵ 25.0.3				+2

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commit: 2139b56

[cubic-dev-ai]

No issues found across 11 files