feat: distinguish 404 permanent failures from temporary API errors

[Yashaswini-K-P]

Description

Updated scripts/analyze-inactivity.js to distinguish between temporary API errors and permanent account deletions, routing 404 errors into invalid-users.json for manual verification.

Linked Issue

Fixes #353

Changes Made

• Updated fetchData to return { data, status }.
• Implemented logic to read, merge, and alphabetically sort entries in invalid-users.json.
• Separated 404 permanent account failures from temporary network/server failures in the sync loop.

Type of Change

• Bug fix
• New feature
• UI/Visual update
• Documentation update
• Refactor

Testing

• Tested locally
• Tested on mobile viewport (if applicable)
• No console errors introduced

Checklist

• My code follows the project's coding style
• I have formatted my code locally by running npx prettier --write . before submitting
• I am submitting my PR from a dedicated feature/* branch, not the main branch
• I have performed a self-review of my code
• My changes generate no new warnings or errors
• I have updated documentation if required
• I have linked the relevant issue

Screenshots / Screen Recording

N/A (Backend synchronization logic update)

[github-actions]

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