fix(cli): skip undefined cues during incremental batch push

[AndreyHirsa]

Summary

Fix VTT push crash when translation API batches responses, causing webvtt.compile to throw on undefined cue text values.

Changes

• Skip empty cues in VTT push
• Each batch writes a partial VTT file; subsequent batches read it back and build on it until complete

Visuals

N/A

Checklist

• Changeset added (if version bump needed)
• Tests cover business logic (not just happy path)
• No breaking changes (or documented below)

Summary by CodeRabbit

• Bug Fixes
  • VTT incremental batch pushing now correctly skips undefined cues, improving handling of edge cases during video text track processing.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 3982e366-fbef-4f78-baa8-380e458ae841

📥 Commits

Reviewing files that changed from the base of the PR and between 2f6438f and 69d35bc.

📒 Files selected for processing (2)

• .changeset/polite-cats-rhyme.md
• packages/cli/src/cli/loaders/vtt.ts

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📝 Walkthrough

Walkthrough

A new changeset file was added to mark a patch-level release. The VTT loader's push method was modified to filter out cue entries with undefined or falsy text values during batch payload transformation, changing from a map() to a reduce() implementation.

Changes

Cohort / File(s)	Summary
Changeset .changeset/polite-cats-rhyme.md	Added patch-level release marker for lingo.dev package documenting the VTT cue filtering behavior.
VTT Loader packages/cli/src/cli/loaders/vtt.ts	Modified push method to use reduce() instead of map(), skipping cue emissions for entries with falsy text values while preserving cue structure for valid entries.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• PR #1990: Filters out undefined/null subtitle texts in both srt.ts and vtt.ts loaders using similar logic patterns
• PR #2057: Modifies the vtt.ts push implementation to handle originalInput and reinsertion of STYLE/REGION blocks

Suggested reviewers

• cherkanovart

Poem

🐰 VTT cues now skip the undefined dance,
No empty text gets a second chance,
Reduce and filter, clean and bright,
Batch pushing handled just right! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: skipping undefined cues during VTT incremental batch push, which matches the core code modification.
Description check	✅ Passed	The description covers the summary and changes but is missing tests section details; however, only the 'Tests cover business logic' checkbox is unchecked, which is acceptable.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/vtt-batch-push

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