Fix Remotion Studio bundling; add caption translation and RTL support

[neutral-Stage]

Summary

• Fixes npm start / Remotion Studio: remotion.config.ts + src/remotion-entry.tsx.
• OpenAI caption translation: translateCaptionData(), captioneer translate, optional textDirection on AnimatedCaptions.
• Hardening (bot review): assertValidTargetLanguageTag() (strict safe BCP-47 subset for prompts), assertCaptionDataShape() for parsed JSON, 120s default fetch timeout (timeoutMs option), 25-segment batching per API call, CLI JSON parse + validation + error handling.
• CI: Pages deploy only on push to main.

Testing

• npm run build
• npx tsc --noEmit
• npx remotion compositions
• npx captioneer --help

Notes

• Translation requires OPENAI_API_KEY (or --api-key).
• Target language must match ^[a-zA-Z0-9]+(-[a-zA-Z0-9]+)*$ (e.g. es, fr-CA, zh-Hans).

  

[kilo-code-bot]

Code Review Roast 🔥

Verdict: No Issues Found | Recommendation: Merge

Oh wait, this PR is actually clean. I need to sit down. I had my flamethrower warmed up and everything.

All 5 previously flagged issues have been fixed:

Previous Issue	Fix
⚠️ Prompt injection via targetLanguage	✅ assertValidTargetLanguageTag() with strict regex validation
💡 fetch() with no timeout	✅ fetchOpenAIChat() with AbortController + 120s default
💡 No chunking for large files	✅ Batching with SEGMENT_BATCH_SIZE = 25
💡 Zero JSON validation in CLI	✅ assertCaptionDataShape() validates full structure
💡 Missing try-catch in translate CLI	✅ Full try/catch with typed error handling

🏆 Best part: You didn't just paper over the issues — you actually extracted assertValidTargetLanguageTag and assertCaptionDataShape as exported utility functions so library consumers get the same protection. That's the kind of defensive API design that makes me think someone's been burned before. The timeoutMs option with a sensible default, the batch-size constant, and the AbortController pattern in fetchOpenAIChat are all textbook. I'm almost suspicious — who are you and what have you done with the developer who wrote the first version?

📊 Overall: Like watching someone clean up after a party — the place was a disaster, but now it's spotless. All previous findings addressed with quality fixes. Ship it.

Files Reviewed (8 files)

• src/translate.ts - was 3 issues, now clean ✅
• src/cli.ts - was 2 issues, now clean ✅
• src/index.ts - clean ✅
• src/components/AnimatedCaptions.tsx - clean
• src/types.ts - clean
• src/remotion-entry.tsx - clean
• remotion.config.ts - clean
• .github/workflows/ci.yml - clean

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_{Reviewed by glm-5 · 465,767 tokens}

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