fix: resolve TypeScript ESLint warnings

[Srushti-Kamble14]

Description

Implemented the TypeScript/ESLint cleanup across the reported files and the rest of the lint surface.

Fixes #1783

Type of Change

• Bug fix (non-breaking change that fixes an issue)

Changes Made

1. Removed unused imports, variables, helpers, and dead component code.
2. Replaced explicit any usages with safer local types in blog data, GitHub service, stats provider, navbar injection, courses, ebooks, sidebar items, and leaderboard.
3. Kept the changes behavior-preserving and scoped to lint/type safety cleanup

Checklist

• My code follows the style guidelines of this project.
• I have tested my changes across major browsers and devices
• My changes do not generate new console warnings or errors .
• I ran npm run build and attached screenshot(s) in this PR.
• This is already assigned Issue to me, not an unassigned issue.

[vercel]

@Srushti-Kamble14 is attempting to deploy a commit to the recode Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

Thank you for submitting your pull request! 🙌 We'll review it as soon as possible. The estimated time for response is 5–8 hrs.

In the meantime, please provide all necessary screenshots and make sure you run - npm build run , command and provide a screenshot, a video recording, or an image of the update you made below, which helps speed up the review and assignment. If you have questions, reach out to LinkedIn. Your contributions are highly appreciated!😊

Note: I maintain the repo issue every day twice at 8:00 AM IST and 9:00 PM IST. If your PR goes stale for more than one day, you can tag and comment on this same issue by tagging @sanjay-kv.

We are here to help you on this journey of open source. Consistent 20 contributions are eligible for sponsorship 💰

🎁 check our list of amazing people we sponsored so far: GitHub Sponsorship. ✨

📚Your perks for contribution to this community 👇🏻

1. Get free Consultation use code recode50 to get free: Mentorship for free.

2. Get the Ebook for free use code recode at checkout: Data Science cheatsheet for Beginners.

3. Check out this weekly Newsletter: Sanjay's Newsletter.

If there are any specific instructions or feedback regarding your PR, we'll provide them here. Thanks again for your contribution! 😊

[github-actions]

✅ Synchronized metadata from Issue #1783:

• Labels: level 1, recode, medium, gssoc:approved, type:testing, type:devops
• Milestone: recode:launch 3.0

[Adez017]

@Srushti-Kamble14 resolve the merge commit and @sanjay-kv need to trigger the CI and thorough testing to verify that there are no any breakings or changes been there , too many file changes at a time need a careful investigation

[Adez017]

need a full testing on this branch