[Frontend] Implement Loading Skeleton States

[Pushkarini579]

Users experience a "pop-in" effect when navigating to the history or results pages.

• Create a reusable Skeleton component using Tailwind/CSS.
• Implement skeleton loaders for the history list and the analysis result sections to improve perceived performance.

[AkshuBalkitta]

@Pushkarini579 I would like to work on this issue under GSSoC 2026. Pls. assign this to me.

[Pushkarini579]

i have assigned... start working fast

[AkshuBalkitta]

@Pushkarini579 Thank you for assigning the issue to me. I'll create the PR soon.

[AkshuBalkitta]

@Pushkarini579 I've created the PR. Kindly review it and let me know.

[AkshuBalkitta]

@Pushkarini579 Is there any issue with my PR? Kindly let me know if any.