Add Bark notification support and normalize CEAC case matching

[Nishikori-Yui]

Summary

• Adds optional Bark notification support using Bark API V2, with configurable server, group, and sound.
• Updates the example environment variables, GitHub Actions workflow, and English/Chinese documentation.
• Normalizes CEAC application numbers before comparison to avoid failures caused by formatting differences.

Validation

• uv run python -m unittest discover -v — 5 tests passed
• uv run python -m compileall -q CEACStatusBot trigger.py tests
• Completed a live CEAC query and successfully received the resulting Bark notification.