feat: add ShareProfileButton to dashboard for copying public profile …

[Bhavy12-cell]

Summary

Closes #2448

Problem

Users had no quick way to copy their public profile URL from the
dashboard. They had to manually find or construct the URL.

Solution

Created a new ShareProfileButton component and placed it next to
the existing Share Profile link in the dashboard header.

Modified Files

• src/components/DashboardHeader.tsx
  • Added import for ShareProfileButton
  • Placed ShareProfileButton next to the Share Profile link
    in both desktop and mobile layouts

Checklist

• ✅ ShareProfileButton.tsx component created
• ✅ Button placed in dashboard header near avatar
• ✅ Clipboard copy works with success toast
• ✅ Error fallback handled with destructive toast
• ✅ Icon switches Link2 → Check for 2s after copy
• ✅ No new dependencies — uses lucide-react and sonner already in project
• ✅ Works in both desktop and mobile layouts

[github-actions]

GSSoC Label Checklist 🏷️

@Umbrella-io — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[Priyanshu-byte-coder]

This PR has merge conflicts with main. Please rebase or resolve conflicts and push again.