SOLVED: Issue persisting 'Solved' state

[kiing-dom]

Problem

Previously, when a user opened a LeetCode problem page (e.g., by clicking a link from the popup or options page), the
extension’s content script would overwrite the problem’s data in storage, removing the "Solved" status and solved timestamp. This caused solved problems to appear as unsolved and disappear from the recent problems list.

Solution:

The content script was updated to always preserve the "Solved" status and solvedAt timestamp when updating problem data on page load. Now, only non-status fields (like title, difficulty, tags, etc.) are updated unless the user actually solves the problem again. The "Solved" status and solvedAt timestamp are only changed when a new solution is submitted and accepted.

Result:

Solved problems now remain marked as solved and persist in the recent problems list, regardless of how or when the user opens the problem page. This ensures accurate and consistent tracking of solved problems.

Resolves #2