fix: [Good First Issue] 🌸 Add new Japan Fact 236 - Beginner-Friendly

[JiwaniZakir]

Fixes #8888

Adds fact #236 to community/content/japan-facts.json about the Japanese concept of 'yoin' (余韻). The file was missing a trailing comma on the previous last entry, which has been corrected as part of appending the new entry. No logic changes -- purely a data addition to the facts array.

[tentoumushii]

🎉 Thanks for your Pull Request, @JiwaniZakir!

We appreciate your contribution to KanaDojo!

Pre-merge checklist:

• You starred our repo ⭐
• Code follows project style guidelines
• Changes have been tested locally
• PR title is descriptive
• If this closes an issue, it's linked with Closes #<number>

A maintainer will review your PR shortly. In the meantime, make sure all CI checks pass. You can run npm run check locally to match CI.

ありがとうございます! 🙏

[tentoumushii]

🤖 Auto-Review: ✅ Passed

This fact contribution has passed automated validation!

Checks passed:

• ✅ File format is correct
• ✅ Content is valid
• ✅ Related issue found

📎 Linked issue: #8888

Once the quality check passes, this PR will be automatically approved for merge.