Optimize sync engine for stale users

[Yashaswini-K-P]

Description

This PR optimizes the 5-minute leaderboard synchronization engine (scripts/sync-leaderboard.js) to handle growing user profiles efficiently. Instead of executing heavy API network requests for completely inactive or stale profiles every 5 minutes, the script now ingests the newly created inactive-users.json tracking file at startup.

Profiles flagged as stale completely bypass the fetchData() network call, and their last known snapshot records are recycled directly from the previous execution's overall dataset. This heavily reduces external network load, avoids API rate-limiting blocks, and significantly accelerates the GitHub Actions workflow execution times.

Linked Issue

Fixes #188

Changes Made

• Lookup Set Initialization: Added startup logic to parse inactive-users.json and loaded the profile IDs into a high-performance Set lookup structure.
• Short-Circuit Verification: Configured a validation rule within the core user-tracking loop to isolate inactive user IDs.
• Snapshot Recycling: Integrated data recovery logic that copies stable user histories directly from historyMap into the new overallData payload when a network call is bypassed.

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

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[Yashaswini-K-P]

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