feat: add weekly contest 489 and biweekly contest 176

[yanglbme]

No description provided.

[Copilot]

Pull request overview

This PR adds documentation for two new LeetCode contests (Weekly Contest 489 and Biweekly Contest 176) to the repository's index files. The changes integrate 8 new problem entries (problems 3838-3845) into the bilingual documentation system, maintaining consistency with the established format for contest problem indexing.

Changes:

• Added 4 problems from Weekly Contest 489 (3842-3845) to English and Chinese problem indices
• Added 4 problems from Biweekly Contest 176 (3838-3841) to English and Chinese problem indices
• Updated contest listing pages with new contest information including dates, times, and participant counts
• Minor whitespace change in main README.md

Reviewed changes

Copilot reviewed 38 out of 45 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
solution/README_EN.md	Added 8 new problem entries (3838-3845) to the English problem index table
solution/README.md	Added 8 new problem entries (3838-3845) to the Chinese problem index table
solution/CONTEST_README_EN.md	Added Weekly Contest 489 and Biweekly Contest 176 sections with problem links
solution/CONTEST_README.md	Added Weekly Contest 489 and Biweekly Contest 176 sections with contest metadata (dates, times, participant counts) and problem links
README.md	Whitespace-only change to a comment line (unrelated to contest additions)

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[Copilot]

This whitespace-only change to the indentation of the comment appears unrelated to the stated purpose of adding contest problems. This type of incidental change should be avoided in focused PRs as it makes the diff harder to review and understand. Consider reverting this change or including it in a separate formatting-focused commit.

Suggested change

	<!-- 排序算法、待补充 -->
	- 排序算法（待补充）