fix(react-email): render email templates in separate nodejs process to avoid OOM issues

[framebassman]

closes #2887

---

Summary by cubic

Render React Email templates in separate Node.js processes to prevent OOM on large exports. Each render is isolated, reports progress, cleans up, and surfaces clearer errors; fixes #2887.

• Bug Fixes
  • Compile and ship a worker (dist/commands/export-worker.js) via tsdown; spawn one process per template with Node’s execPath.
  • Pass JSON input via argv; parse worker stdout/stderr as JSON; progress shows Rendering name (i/total); clearer failure output.
  • Worker writes .html or .txt and removes the .cjs build on success.
  • Tests: add a 100-template stress suite; split Vitest into functional and stress projects; default test runs functional, add test:stress; fix functional import paths.

^{Written for commit 6515641. Summary will update on new commits.}

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Latest commit: 6515641

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commit: 6515641

[cubic-dev-ai]

No issues found across 1 file

[cubic-dev-ai]

1 issue found across 6 files (changes from recent commits).

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="packages/react-email/src/commands/testing/stress/export.spec.ts">

<violation number="1" location="packages/react-email/src/commands/testing/stress/export.spec.ts:10">
P2: `fsPromises.rm(emailsDir)` is called without `recursive/force` and the directory is never recreated, so the test will throw ENOENT on first run and `fsPromises.cp` will fail because the parent directory doesn't exist.</violation>
</file>

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