fix(cli): avoid lint-translations UnicodeEncodeError on legacy consoles

[lntutor]

Fixes #2997

Summary

• add a safe print helper for translation lint output
• degrade emoji markers when stdout cannot encode them instead of crashing
• cover both error and success paths with legacy cp1252 stdout regression tests

Verification

• manual reproduction with cp1252-wrapped stdout no longer crashes
• uv run --no-project pytest backend/tests/test_translations.py
• uv run --no-project ruff check backend/chainlit/translations.py backend/tests/test_translations.py

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Summary by cubic

Prevents the CLI translation linter from crashing on consoles that can’t encode emojis (e.g., cp1252). Output now degrades safely instead of raising UnicodeEncodeError.

• Bug Fixes
  • Added _safe_print to handle unencodable characters based on sys.stdout.encoding.
  • Replaced direct print calls with _safe_print in lint output.
  • Added regression tests using a cp1252-wrapped stdout for both error and success paths.

^{Written for commit 76b4752. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}