feat: only upload if settings have changed (Issue #508)

[qjyqjy1]

Short description of what this resolves:

This PR implements a content-based check before uploading settings to Gist. It prevents unnecessary uploads when no changes are detected, as requested in Issue #508.

Changes proposed in this pull request:

• Added a content comparison check in src/sync.ts before the upload process starts.
• Modified package.nls.json to include a new localization string for the "no changes detected" info message.
• If no changes are found between local files and remote Gist files, the upload is skipped and a message is shown to the user.

Fixes: #508

How Has This Been Tested?

• Verified the comparison logic between local allSettingFiles and remote gistObj.data.files.
• Ensured the upload process only proceeds if at least one file has a content mismatch.

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IssueHunt Summary

Referenced issues

This pull request has been submitted to:

• #508: Compare Local & Gist Settings | Show & upload only changes

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