feat: add repository collections using localStorage

[Ruchira807]

Summary

Implements repository collections using localStorage, allowing users to organize repositories into named collections.

Features

• Create repository collections
• Rename collections
• Delete collections
• Collections persist across page refreshes
• Dashboard section for managing collections

Related Issue

Closes #32

Type of Change

• New feature

Testing

• Tested locally
• npm run lint passes
• npm run build passes

Checklist

• Code follows project conventions
• Linked issue

[vercel]

@Ruchira807 is attempting to deploy a commit to the suyashyadav1709-9626's projects Team on Vercel.

A member of the Team first needs to authorize it.

[Ruchira807]

@Sparkyyy45 kindly review.