Summary

Add a dedicated check command that exits with non-zero code when translations need updating, replacing the lingo.dev i18n --frozen functionality we're deprecating in the future (in favor of run command).

Requirements

• Create new check command that validates translation state without making changes
• Reuse run command's setup and plan phases
• Exit with code 1 if plan phase generates any tasks (tasks.length > 0)
• Exit with code 0 if no tasks needed (everything up-to-date)
• Display summary of what needs updating before exiting

Implementation

Core Approach

The check and run commands should reuse the common logic.

Key Benefits

1. Zero duplication: Reuses all validation logic
2. Consistency: Same detection logic as actual translation process
3. Maintainability: Single source of truth for what needs updating
4. Simplicity: ~50 lines of code instead of reimplementing validation

Task Detection

The run command's plan phase already creates tasks for:

• Source file changes (checksum mismatches)
• Missing translations
• New locales
• Configuration changes

By checking tasks.length > 0, we detect all these cases automatically.

Example Usage

# CI/CD pipeline
- name: Check translations
  run: `npx lingo.dev@latest check`
  # Fails pipeline if translations need updating