Adjust CSS specificity to ensure Japanese font is properly applied - specify font family explicitly (#2778)

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## Self Checklist

- [x] I wrote a PR title in **English** and added an appropriate
**label** to the PR.
- [x] I wrote the commit message in **English** and to follow [**the
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- [x] I [added the
**changeset**](https://github.com/changesets/changesets/blob/main/docs/adding-a-changeset.md)
about the changes that needed to be released. (or didn't have to)
- [x] I wrote or updated **documentation** related to the changes. (or
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## Related Issue
- #2776
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<!-- Fixes #0000 -->

## Summary

<!-- Please brief explanation of the changes made -->
css 적용 우선순위로 인해 일본어일 때 타이포그래피 폰트의 오버라이드가 적용되지 않는 문제를 재수정합니다.

## Details

<!-- Please elaborate description of the changes -->
- 현재 css 레이어 우선순위는 tokens > base > components 로 설정되어 있습니다.
- 토큰을 오버라이드 했던 기존 코드는 base 레이어에서 정의되어 있습니다.
- 토큰의 우선순위 상 tokens가 base보다 우선하기 때문에 해당 코드는 동작하지 않았습니다.
- [최초
코드](https://github.com/channel-io/bezier-react/pull/2764/changes#diff-d5343edd2cbd4060cb12d851b2ce7b8776194248a36fa05f6a4bf7c9dff9cfdfL19-R22)와
같이 font-family를 명시적으로 설정하는 방향으로 문제를 해결합니다.

### Breaking change? (Yes/No)

<!-- If Yes, please describe the impact and migration path for users -->
No
## References

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

## 릴리스 노트

* **버그 수정**
  * Japanese 폰트가 제대로 적용되도록 CSS 우선순위를 조정했습니다.
  * 기본 폰트 가족 설정을 개선하여 다언어 폰트 처리를 최적화했습니다.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: timok1m

.changeset/yellow-lizards-clean.md

@@ -0,0 +1,5 @@
+---
+'@channel.io/bezier-react': patch
+---
+
+Adjust CSS specificity to ensure Japanese font is properly applied - specify font family explicitly

packages/bezier-react/src/styles/_base.scss

@@ -1,5 +1,5 @@
 :where(:root, :host) {
-  font-family: var(--typography-text-font-family);
+  font-family: var(--typography-font-family-sans-kr);
   font-size: 62.5%; // 10/16 = 0.625. Make REM calculations easier.
   color: var(--color-text-neutral);
   color-scheme: light;
@@ -15,15 +15,12 @@
   color-scheme: dark;
 }
 
-[data-bezier-theme='dark']:lang(ja),
-[data-bezier-theme='light']:lang(ja) {
-  --typography-heading-font-family: var(--typography-font-family-sans-jp);
-  --typography-text-font-family: var(--typography-font-family-sans-jp);
-  --typography-display-font-family: var(--typography-font-family-sans-jp);
+:lang(ja) {
+  font-family: var(--typography-font-family-sans-jp);
 }
 
 code {
-  font-family: var(--typography-code-font-family);
+  font-family: var(--typography-font-family-monospace);
 }
 
 ::placeholder {