Feature/skeleton loaders

[Nareshkumawat-star]

PR Description

This PR replaces the generic activity spinners (<Loader />) with animated Skeleton loaders for content-fetching screens (GET operations) to significantly improve perceived performance and polish.

Key Changes:

• Created a lightweight, dependency-free Skeleton component utilizing the native Animated API for a smooth shimmer effect.
• Created ArticleCardSkeleton to mimic the structure of an ArticleCard.
• Created ArticleDetailSkeleton to mimic the layout of ArticleScreen.
• Integrated ArticleCardSkeleton into HomeScreen, ProfileScreen, and UserProfileScreen for loading states.
• Integrated ArticleDetailSkeleton into ArticleScreen for article data fetching.
• Intentionally retained the existing <Loader /> spinners for mutations (e.g., liking, requesting edits) per UX best practices.

Type of Change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update

Select your work-area

• Frontend
• Backend
• Documentation
• Others

Related Issue

N/A

Add your Work Example

(Optional: Add screenshots or screen recordings showing the animated skeletons during slow network simulated loads)

Fixes #1276

Checklist

• I have updated my branch and synced it with the project's 'develop' branch before making this PR.
• I have optimized the file changes.
• I have added a snapshot of my work example.
• I have made a PR to the project's develop branch.

Undertaking

• My code follows the style guidelines of this project.
• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.

[github-actions]

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